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Peptidase
Kinds of Peptidase Terms modified by Peptidase Selected AbstractsChemInform Abstract: Design and Synthesis of Unsymmetrical Peptidyl Urea Inhibitors of Aspartic Peptidases.CHEMINFORM, Issue 49 2001Natalie A. Dales Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: From Peptides to Non-Peptide Peptidomimetics: Design and Synthesis of New Piperidine Inhibitors of Aspartic Peptidases.CHEMINFORM, Issue 49 2001Matthew G. Bursavich Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] Glycaemic goals in patients with type 2 diabetes: current status, challenges and recent advancesDIABETES OBESITY & METABOLISM, Issue 6 2010K. Khunti Recommendations for the management of type 2 diabetes include rigorous control of blood glucose levels and other risk factors, such as hypertension and dyslipidaemia. In clinical practice, many patients do not reach goals for glycaemic control. Causes of failure to control blood glucose include progression of underlying pancreatic , -cell dysfunction, incomplete adherence to treatment (often because of adverse effects of weight gain and hypoglycaemia) and reluctance of clinicians to intensify therapy. There is increasing focus on strategies that offer potential to improve glycaemic control. Structured patient education has been shown to improve glycaemic control and other cardiovascular risk factors in people with type 2 diabetes. Payment of general practitioners by results has been shown to improve glycaemic control. New classes of glucose-lowering agents have expanded the treatment options available to clinicians and patients and include the dipeptidyl peptidase 4 (DPP-4) inhibitors and glucagon-like peptide-1 (GLP-1) receptor agonists. These new classes of therapy and other strategies outlined above could help clinicians to individualize treatment and help a greater proportion of patients to achieve long-term control of blood glucose. [source] GLP-1: physiological effects and potential therapeutic applicationsDIABETES OBESITY & METABOLISM, Issue 11 2008Kasper Aaboe Glucagon-like peptide 1 (GLP-1) is a gut-derived incretin hormone with the potential to change diabetes. The physiological effects of GLP-1 are multiple, and many seem to ameliorate the different conditions defining the diverse physiopathology seen in type 2 diabetes. In animal studies, GLP-1 stimulates ,-cell proliferation and neogenesis and inhibits ,-cell apoptosis. In humans, GLP-1 stimulates insulin secretion and inhibits glucagon and gastrointestinal secretions and motility. It enhances satiety and reduces food intake and has beneficial effects on cardiovascular function and endothelial dysfunction. Enhancing incretin action for therapeutic use includes GLP-1 receptor agonists resistant to degradation (incretin mimetics) and dipeptidyl peptidase (DPP)-4 inhibitors. In clinical trials with type 2 diabetic patients on various oral antidiabetic regimes, both treatment modalities efficaciously improve glycaemic control and ,-cell function. Whereas the incretin mimetics induce weight loss, the DPP-4 inhibitors are considered weight neutral. In type 1 diabetes, treatment with GLP-1 shows promising effects. However, several areas need clinical confirmation: the durability of the weight loss, the ability to preserve functional ,-cell mass and the applicability in other than type 2 diabetes. As such, long-term studies and studies with cardiovascular end-points are needed to confirm the true benefits of these new classes of antidiabetic drugs in the treatment of diabetes mellitus. [source] The antibiotic ADEP reprogrammes ClpP, switching it from a regulated to an uncontrolled proteaseEMBO MOLECULAR MEDICINE, Issue 1 2009Janine Kirstein Abstract A novel class of antibiotic acyldepsipeptides (designated ADEPs) exerts its unique antibacterial activity by targeting the peptidase caseinolytic protease P (ClpP). ClpP forms proteolytic complexes with heat shock proteins (Hsp100) that select and process substrate proteins for ClpP-mediated degradation. Here, we analyse the molecular mechanism of ADEP action and demonstrate that ADEPs abrogate ClpP interaction with cooperating Hsp100 adenosine triphosphatases (ATPases). Consequently, ADEP treated bacteria are affected in ClpP-dependent general and regulatory proteolysis. At the same time, ADEPs also activate ClpP by converting it from a tightly regulated peptidase, which can only degrade short peptides, into a proteolytic machinery that recognizes and degrades unfolded polypeptides. In vivo nascent polypeptide chains represent the putative primary target of ADEP-activated ClpP, providing a rationale for the antibacterial activity of the ADEPs. Thus, ADEPs cause a complete functional reprogramming of the Clp,protease complex. [source] Digestive peptidases in Tenebrio molitor and possibility of use to treat celiac diseaseENTOMOLOGICAL RESEARCH, Issue 3 2007Elena N. ELPIDINA Abstract Digestion in Tenebrio molitor larvae occurs in the midgut, where there is a sharp pH gradient from 5.6 in the anterior midgut (AM) to 7.9 in the posterior midgut (PM). Accordingly, digestive enzymes are compartmentalized to the AM or PM. Enzymes in the AM are soluble and have acidic or neutral pH optima, while PM enzymes have alkaline pH optima. The main peptidases in the AM are cysteine endopeptidases presented by two to six subfractions of anionic proteins. The major activity belongs to cathepsin L, which has been purified and characterized. Serine post-proline cleaving peptidase with pH optimum 5.3 was also found in the AM. Typical serine digestive endopeptidases, trypsin-like and chymotrypsin-like, are compartmentalized to the PM. Trypsin-like activity is due to one cationic and three anionic proteinases. Chymotrypsin-like activity consists of one cationic and four anionic proteinases, four with an extended binding site. The major cationic trypsin and chymotrypsin have been purified and thoroughly characterized. The predicted amino acid sequences are available for purified cathepsin L, trypsin and chymotrypsin. Additional sequences for putative digestive cathepsins L, trypsins and chymotrypsins are available, implying multigene families for these enzymes. Exopeptidases are found in the PM and are presented by a single membrane aminopeptidase N-like peptidase and carboxypeptidase A, although multiple cDNAs for carboxypeptidase A were found in the AM, but not in the PM. The possibility of the use of two endopeptidases from the AM , cathepsin L and post-proline cleaving peptidase , in the treatment of celiac disease is discussed. [source] Catalytic digestion of human tumor necrosis factor-, by antibody heavy chainFEBS JOURNAL, Issue 18 2010Emi Hifumi It has long been an important task to prepare a catalytic antibody capable of digesting a targeting crucial protein that controls specific life functions. Tumor necrosis factor-, (TNF-,) is a cytokine and an important molecule concerned with autoimmune diseases such as rheumatoid arthritis, chronic obstructive pulmonary disease, and Crohn's disease. A mAb (ETNF-6 mAb) raised against human TNF-, was prepared, and the steric conformation was created by using molecular modeling after the cDNA was sequenced. The heavy chain (ETNF-6-H) of the mAb was considered to possess a catalytic triad-like structure in the complementarity determining regions (CDRs). As a result, ETNF-6-H exhibited a peptidase and a protease activity. In fact, ETNF-6-H predominantly cleaved the Ser5-Arg6 bond of TNF-, at the first step, resulting in the generation of a fragment of , 17 kDa. This fragment was digested to a smaller molecule of 15 kDa by scission of the Gln21-Ala22 bond. The intermediate product was further converted into a fragment of 13.3 kDa by successive cleavage of the Leu36-Leu37 and Asn39-Gly40 bonds. The heavy chain possessed a protease activity against TNF-, with a multicleavage site. [source] Characterization of membrane-bound prolyl endopeptidase from brainFEBS JOURNAL, Issue 17 2008Jofre Tenorio-Laranga Prolyl oligopeptidase (POP) is a serine protease that cleaves small peptides at the carboxyl side of an internal proline residue. Substance P, arginine,vasopressin, thyroliberin and gonadoliberin are proposed physiological substrates of this protease. POP has been implicated in a variety of brain processes, including learning, memory, and mood regulation, as well as in pathologies such as neurodegeneration, hypertension, and psychiatric disorders. Although POP has been considered to be a soluble cytoplasmic peptidase, significant levels of activity have been detected in membranes and in extracellular fluids such as serum, cerebrospinal fluid, seminal fluid, and urine, suggesting the existence of noncytoplasmic forms. Furthermore, a closely associated membrane prolyl endopeptidase (PE) activity has been previously detected in synaptosomes and shown to be different from the cytoplasmic POP activity. Here we isolated, purified and characterized this membrane-bound PE, herein referred to as mPOP. Although, when attached to membranes, mPOP presents certain features that distinguish it from the classical POP, our results indicate that this protein has the same amino acid sequence as POP except for the possible addition of a hydrophobic membrane anchor. The kinetic properties of detergent-soluble mPOP are fully comparable to those of POP; however, when attached to the membranes in its natural conformation, mPOP is significantly less active and, moreover, it migrates anomalously in SDS/PAGE. Our results are the first to show that membrane-bound and cytoplasmic POP are encoded by variants of the same gene. [source] Modulation of inositol 1,4,5-triphosphate concentration by prolyl endopeptidase inhibitionFEBS JOURNAL, Issue 23 2002Ingo Schulz Prolyl endopeptidase (PEP) is a proline-specific oligopeptidase with a reported effect on learning and memory in different rat model systems. Using the astroglioma cell line U343, PEP expression was reduced by an antisense technique. Measuring different second-messenger concentrations revealed an inverse correlation between inositol 1,4,5-triphosphate [Ins(1,4,5)P3] concentration and PEP expression in the generated antisense cell lines. However, no effect on cAMP generation was observed. In addition, complete suppression of PEP activity by the specific inhibitor, Fmoc-Ala-Pyrr-CN (5 µm) induced in U343 and other cell lines an enhanced, but delayed, increase in Ins(1,4,5)P3 concentration. This indicates that the proteolytic activity of PEP is responsible for the observed effect. Furthermore, the reduced PEP activity was found to amplify Substance P-mediated stimulation of Ins(1,4,5)P3. The effect of reduced PEP activity on second-messenger concentration indicates a novel intracellular function of this peptidase, which may have an impact on the reported cognitive enhancements due to PEP inhibition. [source] Expression of cathepsins B, D and L in mouse corneas infected with Pseudomonas aeruginosaFEBS JOURNAL, Issue 24 2001Zhong Dong C57BL/6J naïve and immunized mice were intracorneally infected with Pseudomonas aeruginosa. Semi-quantitative RT-PCR was performed to detect cathepsin gene expression and the results were further confirmed by immunoblot analysis. The enzymatic activities of cathepsins B, D and L were measured by peptidase assays. Immunohistochemical staining was carried out to localize the expression of the cathepsins. Cathepsins B, D and L were detected in the normal cornea by RT-PCR. A peptidase assay revealed activities of all three cathepsins under normal physiological conditions. In naïve mice, enzymatic activities of cathepsins B, D and L were all significantly enhanced when the corneas were infected with P. aeruginosa and the peak of the induction appeared around day 6 postinfection. Immunoblot analysis showed increased expression of cathepsins B, D and L. The infected corneal samples from immunized mice exhibited much lower induction of enzymatic activities compared to those from naïve mice. Immunohistochemistry showed that the expression of cathepsins in the normal cornea was restricted to the epithelial tissue while the induced expression of cathepsins was predominantly in the substantia propria. Our data revealed up-regulated enzymatic activities of cathepsins B, D and L in the naïve corneas infected with P. aeruginosa, which correlated well with the inflammatory response. Immunization of mice against P. aeruginosa attenuated the inducing effect on cathepsin expression caused by infection. The time sequence for induction of cathepsin proteins and enzymatic activities suggests a mechanism of host proteolytic degradation of the extracellular matrix resulting in corneal destruction after P. aeruginosa infection. [source] Biogenesis of Yersinia pestis PsaA in recombinant attenuated Salmonella Typhimurium vaccine (RASV) strainFEMS MICROBIOLOGY LETTERS, Issue 2 2010Ascención Torres-Escobar Abstract Yersinia pestis PsaA is an adhesin important for the establishment of bacterial infection. PsaA synthesis requires the products of the psaEFABC genes. Here, by prediction analysis, we identified a PsaA signal sequence with two signal peptidase (SPase) cleavage sites, type-I and type-II (SPase-I and SPase-II). By Edman degradation and site-directed mutagenesis, the precise site for one of these Spase-I PsaA cleavage sites was located between alanine and serine at positions 31 and 32, respectively. Yersinia pestis psaA expression and the role of the PsaB and PsaC proteins were evaluated in recombinant attenuated Salmonella Typhimurium vaccine strains. PsaA was detected in total extracts as a major 15-kDa (mature) and 18-kDa (unprocessed) protein bands. PsaA synthesis was not altered by a ,A31,,S32 double-deletion mutation. In contrast, the synthesis of PsaA (,A31,,S32) in Y. pestis and delivery to the supernatant was decreased. Otherwise, substitution of the amino acid cysteine at position 26 by valine involved in the SPase-II cleavage site did not show any effect on the secretion of PsaA in Salmonella and Yersinia. These results help clarify the secretion pathway of PsaA for the possible development of vaccines against Y. pestis. [source] Genes for an alkaline d -stereospecific endopeptidase and its homolog are located in tandem on Bacillus cereus genomeFEMS MICROBIOLOGY LETTERS, Issue 1 2003Hidenobu Komeda Abstract Alkaline d -peptidase (Adp) from Bacillus cereus DF4-B is a d -stereospecific endopeptidase acting on oligopeptides composed of d -phenylalanine and the primary structure deduced from its gene, adp, shows a similarity with d -stereospecific hydrolases from Ochrobactrum anthropi strains. We have isolated DNA fragments covering the flanking region of adp from DF4-B genome and found an additional gene, adp2, located upstream of adp. The deduced amino acid sequence of Adp2 showed 96% and 85% identity with those of Adp from B. cereus strains AH559 and DF4-B, respectively. The recombinant Adp2 expressed in Escherichia coli was purified to homogeneity and characterized. It had hydrolyzing activity toward (d -Phe)3, (d -Phe)4, and (d -Phe)6 but did not act on (l -Phe)4, d -Phe-NH2, and l -Phe-NH2, some characteristics that are closely related to those of Adp from strain DF4-B. These results indicate that highly homologous genes encoding d -stereospecific endopeptidases are arranged in a tandem manner on the genomic DNA of B. cereus DF4-B. [source] The archaeal flagellum: a different kind of prokaryotic motility structureFEMS MICROBIOLOGY REVIEWS, Issue 2 2001Nikhil A Thomas Abstract The archaeal flagellum is a unique motility apparatus distinct in composition and likely in assembly from the bacterial flagellum. Gene families comprised of multiple flagellin genes co-transcribed with a number of conserved, archaeal-specific accessory genes have been identified in several archaea. However, no homologues of any bacterial genes involved in flagella structure have yet been identified in any archaeon, including those archaea in which the complete genome sequence has been published. Archaeal flagellins possess a highly conserved hydrophobic N-terminal sequence that is similar to that of type IV pilins and clearly unlike that of bacterial flagellins. Also unlike bacterial flagellins but similar to type IV pilins, archaeal flagellins are initially synthesized with a short leader peptide that is cleaved by a membrane-located peptidase. With recent advances in genetic transfer systems in archaea, knockouts have been reported in several genes involved in flagellation in different archaea. In addition, techniques to isolate flagella with attached hook and anchoring structures have been developed. Analysis of these preparations is under way to identify minor structural components of archaeal flagella. This and the continued isolation and characterization of flagella mutants should lead to significant advances in our knowledge of the composition and assembly of archaeal flagella. [source] Molecular basis of antibiotic resistance and ,-lactamase inhibition by mechanism-based inactivators: perspectives and future directionsFEMS MICROBIOLOGY REVIEWS, Issue 3 2000Christian Therrien Abstract Antibacterial chemotherapy is particularly striking in the family of penicillins and cephalosporins. Over 40 structurally different ,-lactam molecules are available in 73 formulations and the majority of them are currently prescribed for medical use in hospitals. ,-Lactams are well tolerated by humans with few side effects. They interact very specifically with their bacterial target, the d -alanyl- d -alanine carboxypeptidase-transpeptidase usually referred to as dd -peptidase. The outstanding number of ,-lactamases produced by bacteria represent a serious threat to the clinical utility of ,-lactams. The discovery of ,-lactamase inhibitors was thought to solve, in part, the problem of resistance. Unfortunately, bacteria have evolved new mechanisms of resistance to overcome the inhibitory effects of ,-lactamase inactivators. Here, we summarize the diversified mechanistic features of class A ,-lactamases interactions with mechanism-based inhibitors using available microbiological, kinetic and structural data for the prototype TEM ,-lactamases. A brief historical overview of the strategies developed to counteract ,-lactamases will be presented followed by a short description of the chemical events which lead to the inactivation of TEM ,-lactamase by inhibitors from different classes. Finally, an update on the clinical prevalence of natural and inhibitor-resistant enzyme mutants, the total chemical synthesis to design and synthesize a new structure and produced a broad spectrum ,-lactamase inhibitor that mimics the ,-lactam ring, but does not contain it is discussed. [source] BCL11A is a SUMOylated protein and recruits SUMO-conjugation enzymes in its nuclear bodyGENES TO CELLS, Issue 9 2008Takeshi Kuwata BCL11A/EVI9 is a zinc-finger protein predominantly expressed in brain and hematopoietic cells. Previous studies show that BCL11A is involved in acute myelomonocytic leukemia and chronic lymphoid leukemia in mouse and human, respectively. Moreover, BCL11A is localized in the characteristic nuclear body in which BCL6 is co-localized. However, the significance of BCL11A in leukemogenesis and nuclear function remains unknown. In this study we show that BCL11A interacts with UBC9, a small ubiquitin-like modifier (SUMO) E2 conjugating enzyme, and recruits SUMO1 into the nuclear body. A lysine residue at amino acid 634 of BCL11A is SUMOylated but not required for the SUMO1 recruitment. The N-terminal region of BCL11A is responsible for SUMO1 recruitment as well as its nuclear body formation. We also show that SENP2, a SUMO specific peptidase, is co-localized in the nuclear body. These results suggest that BCL11A could be involved in the SUMO conjugation system, and that BCL11A might play an important role in protein modification. [source] Seasonal variation in enzyme activities and temperature sensitivities in Arctic tundra soilsGLOBAL CHANGE BIOLOGY, Issue 7 2009MATTHEW D. WALLENSTEIN Abstract Arctic soils contain large amounts of organic matter due to very slow rates of detritus decomposition. The first step in decomposition results from the activity of extracellular enzymes produced by soil microbes. We hypothesized that potential enzyme activities are low relative to the large stocks of organic matter in Arctic tundra soils, and that enzyme activity is low at in situ temperatures. We measured the potential activity of six hydrolytic enzymes at 4 and 20 °C on four sampling dates in tussock, intertussock, shrub organic, and shrub mineral soils at Toolik Lake, Alaska. Potential activities of N -acetyl glucosaminidase, ,-glucosidase, and peptidase tended to be greatest at the end of winter, suggesting that microbes produced enzymes while soils were frozen. In general, enzyme activities did not increase during the Arctic summer, suggesting that enzyme production is N-limited during the period when temperatures would otherwise drive higher enzyme activity in situ. We also detected seasonal variations in the temperature sensitivity (Q10) of soil enzymes. In general, soil enzyme pools were more sensitive to temperature at the end of the winter than during the summer. We modeled potential in situ,-glucosidase activities for tussock and shrub organic soils based on measured enzyme activities, temperature sensitivities, and daily soil temperature data. Modeled in situ enzyme activity in tussock soils increased briefly during the spring, then declined through the summer. In shrub soils, modeled enzyme activities increased through the spring thaw into early August, and then declined through the late summer and into winter. Overall, temperature is the strongest factor driving low in situ enzyme activities in the Arctic. However, enzyme activity was low during the summer, possibly due to N-limitation of enzyme production, which would constrain enzyme activity during the brief period when temperatures would otherwise drive higher rates of decomposition. [source] Dipeptidyl peptidase expression during experimental colitis in miceINFLAMMATORY BOWEL DISEASES, Issue 8 2010Roger Yazbeck PhD Abstract Background: We have previously demonstrated that inhibition of dipeptidyl peptidase (DP) activity partially attenuates dextran sulfate sodium (DSS) colitis in mice. The aim of this study was to further investigate the mechanisms of this protection. Materials and Methods: Wildtype (WT) and DPIV,/, mice consumed 2% DSS in drinking water for 6 days to induce colitis. Mice were treated with saline or the DP inhibitors Ile-Pyrr-(2-CN)*TFA or Ile-Thia. DP mRNA and enzyme levels were measured in the colon. Glucagon-like peptide (GLP)-2 and GLP-1 concentrations were determined by radioimmunoassay, regulatory T-cells (Tregs) by fluorescence activated cell sorting (FACS) on FOXp3+T cells in blood, and neutrophil infiltration assessed by myeloperoxidase (MPO) assay. Results: DP8 and DP2 mRNA levels were increased (P < 0.05) in WT+saline mice compared to untreated WT mice with colitis. Cytoplasmic DP enzyme activity was increased (P < 0.05) in DPIV,/, mice at day 6 of DSS, while DP2 activity was increased (P < 0.05) in WT mice with colitis. GLP-1 (63%) and GLP-2 (50%) concentrations increased in WT+Ile-Pyrr-(2-CN)*TFA mice compared to day-0 controls. MPO activity was lower in WT+Ile-Thia and WT+Ile-Pyrr-(2-CN)*TFA treated mice compared to WT+saline (P < 0.001) at day 6 colitis. Conclusions: DP expression and activity are differentially regulated during DSS colitis, suggesting a pathophysiological role for these enzymes in human inflammatory bowel disease (IBD). DP inhibitors impaired neutrophil recruitment and maintenance of the Treg population during DSS-colitis, providing further preclinical evidence for the potential therapeutic use of these inhibitors in IBD. Finally, DPIV appears to play a critical role in mediating the protective effect of DP inhibitors. Inflamm Bowel Dis 2010 [source] Enzymes involved in flavour formation by bacteria isolated from the smear population of surface-ripened cheeseINTERNATIONAL JOURNAL OF DAIRY TECHNOLOGY, Issue 1 2004A G Williams Twenty-five bacterial isolates recovered from the surface population of smear-ripened cheese were assigned phenotypically as Brevibacterium spp., Corynebacterium spp. and Aureobacterium spp. using the Biolog GP2 microplate system and database. The range and activity of hydrolytic enzymes involved in the formation of cheese flavour constituents were monitored in cell-free lysates of the isolates. Esterase activity and the presence of a range of enzymes involved in amino acid release and breakdown was confirmed in all strains examined although there were pronounced interspecies and strain differences in the level of activity detected. Peptidolytic activities present in the smear bacteria included dipeptidyl peptidase and aminopeptidases that cleaved various N-terminal amino acids including proline. Subsequent breakdown of the released aromatic and branched-chain amino acids was mediated by ,-keto acid dependent aminotransferase action and several of the isolates were able to form thiols from sulphur-containing amino acid precursors. It was confirmed that the enzymic activity of the smear population could be manipulated by the use of defined starter cultures comprising selected combinations of smear isolates. The hydrolytic activities of the smear bacteria are involved in the generation of cheese flavour compounds and the enzyme profile is thus an important selection criterion for strains to be evaluated for use in defined surface smear preparations. [source] Expression and secretion of an ,-amylase gene from a native strain of Bacillus licheniformis in Escherichia coli by T7 promoter and putative signal peptide of the geneJOURNAL OF APPLIED MICROBIOLOGY, Issue 6 2003M. Shahhoseini Abstract The gene encoding a hyperthermostable , -amylase from a Bacillus licheniformis native strain was cloned in pET24d transcription vector containing T7 promoter, and expressed in Escherichia coli BL21(DE3) cells. Having confirmed the , -amylase activity through activity staining method on SDS,PAGE gel, the yields of production were determined in two separated intra and inter-cellular phases and compared using enzymatic assay methods. Extracellular production of the active recombinant enzyme implies the recognition of the putative signal peptide of this Bacillus sp. by E. coli secretory system. This may be because of the amino acid sequence of this signal peptide which covers all the structural parameters of a standard signal peptide processed by Lep B, the major signal peptidase in E. coli secretory system. This study recommends the use of this signal peptide for extracellular production of other foreign proteins in E. coli. [source] Alterations in the expression of intestinal enzymes in rats exposed to nickelJOURNAL OF APPLIED TOXICOLOGY, Issue 5 2006Amika Singla Abstract The effect of feeding nickel (50 mg kg,1 body weight) daily for 7 days was studied on the development of various brush border enzymes across the crypt,villus axis. The activities of brush border maltase (P < 0.05), lactase (P < 0.05), alkaline phosphatase (P < 0.05) and leucine amino peptidase (P < 0.05) were augmented in purified brush borders, whereas sucrase, trehlase (P < 0.01) and glutamyl transpeptidase (P < 0.05) were reduced in nickel fed animals compared with controls. Kinetic and heat inactivation studies with brush border sucrase and alkaline phosphatase confirmed these findings. Western blot analysis of alkaline phosphatase showed a strong signal for the enzyme protein but a reduced level of sucrase antigen in nickel fed rat intestine compared with the controls. These findings suggest that the expression of various brush border enzymes along the crypt,villus axis is modulated in rat intestine exposed to nickel, which may disrupt the digestive functions of the intestinal tissue. Copyright © 2006 John Wiley & Sons, Ltd. [source] Clinical and microbiological studies of periodontal disease in Sjögren's syndrome patientsJOURNAL OF CLINICAL PERIODONTOLOGY, Issue 2 2002B. Kuru Abstract Background: Little is known about the periodontal status of patients with Sjögren's Syndrome (SS), a chronic inflammatory autoimmune disease characterized by xerophthalmia and xerostomia. The aim of the present study was to evaluate whether the periodontal status of SS patients, in terms of clinical and microbiological parameters, differs from systemically healthy age- and gender-matched controls. Methods: 8 primary SS and 10 secondary SS patients were examined in comparison with 11 control subjects. All patients were diagnosed by the European Community Criteria. Control subjects were systemically healthy and not undergoing periodontal treatment. The comparison of clinical status was made in terms of mean periodontal parameters (plaque index, gingival index, gingival recession, probing pocket depth, probing attachment level and bleeding on probing) as well as the frequency distribution of probing pocket depth and probing attachment level measurements. Microbiological assays of the subgingival dental plaque samples were carried out by both a chairside enzyme test (Periocheck®) for the detection of peptidase activity (PA) and a polymerase chain reaction (PCR) analysis for 9 selected periodontal micro-organisms (Actinobacillus actinomycetemcomitans, Fusobacterium nucleatum, Prevotella intermedia, Treponema denticola, Porphyromonas gingivalis, Eikenella corrodens, Campylobacter rectus, Bacteroides forsythus, Streptococcus oralis). Results: The occurrence, severity and extent of periodontal lesions were not significantly different between the 3 patient groups for all periodontal parameters examined. No significant differences in the sub-gingival plaque samples from control, primary or secondary SS patients for the PA test, frequency or type of periodontal micro-organisms observed. Conclusion: No significant differences could be detected in either clinical or microbiological parameters of primary or secondary SS patients compared with that of control subjects. The results of the present study thus support the notion that the periodontal status of patients with SS do not differ from systemically healthy age- and gender-matched controls. Zusammenfassung Hintergrund: Es ist wenig über den parodontalen Status von Patienten mit Sjögren Syndrom (SS) bekannt, einer chronischen entzündlichen Autoimmunerkrankung, die durch Xerophtalmie und Xerostomie charakterisiert ist. Das Ziel der vorliegenden Studie war zu überprüfen, ob der parodontale Status der SS-Patienten bi Berücksichtigung der klinischen und mikrobiologischen Parameter von demjenigen bei systemisch gesunden alters- und geschlechtspassenden Kontrollen abweicht. Methoden: 8 primäre SS und 10 sekundäre SS Patienten wurden mit 11 Kontrollpersonen vergleichend untersucht. Alle Patienten waren durch Kriterien der EU diagnostiziert. Die Kontrollpersonen waren systemisch gesund und erhielten keine parodontale Behandlung. Der Vergleich des klinischen Status wurde auf der Basis von mittleren parodontalen Parametern (Plaque-Index, Gingivaindex, gingivale Rezession, Sondierungstiefe, Stützgewebeniveau, Provokationsblutung) sowie der Verteilungsmuster der Sondierungstiefe und des Stützgewebeniveaus vorgenommen. Mikrobiologische Assay's von subgingivalen Plaqueproben wurden sowohl mit einem chairside Enzymtest (Periocheck®) für die Feststellung der Peptidaseaktivität (PA) und einer Polymerasekettenreaktion (PCR) für 9 selektierte parodontale Mikroorganismen (Actinobacillus actinomycetemcomitans, Fusobacterium nucleatum, Prevotella intermedia, Treponema denticola, Porphyromonas gingivalis, Eikenella corrodens, Campylobacter rectus, Bacteroides forsythus, Streptococcus oralis) durchgeführt. Ergebnisse: Das Vorkommen, die Schwere und die Ausdehnung von parodontalen Läsionen unterschied sich nicht signifikant zwischen den 3 Patientengruppen für alle geprüften parodontalen Parameter. Es gab auch keine signifikanten Differenzen in den subgingivalen Plaqueproben von den Kontrollen, den primären oder sekundären SS Patienten für die PA Teste und Frequenz oder Art von beobachteten parodontalen Mikroorganismen. Schlussfolgerung: Es konnten keine signifikanten Differenzen sowohl bei den klinischen oder mikrobiologischen Parametern von primären oder sekundären SS Patienten im Vergleich mit Kontrollpersonen entdeck werden. Die Ergebnisse der vorliegenden Studie unterstützen die Ansicht, dass sich der parodontale Status von Patienten mit SS nicht von demjenigen gesunder alters- und geschlechtspassender Kontrollen unterscheidet. Résumé Origine: On en sait peu sur l'état parodontal des patients atteints du syndrome de Sjögren (SS), une maladie chronique autoimmune inflammatoire caractérisée par une xérophtalmie et une xérostomie. Le but de cette étude était d'évaluer si l'état parodontal des patients SS, en terme de paramètres cliniques et microbiologiques était différent de sujets contrôles en bonne santé générale du même âge et du méme sexe. Méthodes: 8 patients atteints de SS primaires et 10 de SS secondaires furent examinés et comparés avec des sujets contrôles. Tous les patients étaient diagnostiqués selon les critères de la communauté européenne. Les sujets contrôles étaient en bonne santé générale et ne suivaient pas de traitement parodontal. La comparaison des états parodontaux fut réalisée pour les paramètres cliniques moyens (indice de plaque, gingival, récession gingivale, profondeur de poche au sondage, niveau d'attache et saignement au sondage) et aussi pour la frèquence de distribution des mesures des profondeurs de poche au sondage et des niveaux d'attache. Les tests microbiologiques des échantillons de plaque sous-gingivale ont été réalisés à la fois par un test enzymatique au fauteuil (Periocheck®) pour la détection de l'activité peptidase (PA) et par réaction de polymérase en chaine (PCR) pour 9 micro-organismes parodontaux sélectionnés (Actinobacillus actinomycetemcomitans, Fusobacterium nucleatum, Prevotella intermedia, Treponema denticola, Porphyromonas gingivalis, Eikenella corrodens, Campylobacter rectus, Bacteroides forsythus, Streptococcus oralis). Résultats: La survenue, la sévérité et l'étendue de la maladie parodontale n'étaient pas significativement différente entre les 3 groupes de patients pour tous les paramètres parodontaux examinés. Aucune différence significative ne fut observée entre les échantillons de plaque sous-gingivale des contrôles et ceux des patients atteints de SS primaire et secondaire, pour PA, la frèquence ou le type de micro-organismes. Conclusions: Aucune différence significative ne put être détectée, ni pour les paramètres cliniques, ni pour les paramètres microbiologiques des patients atteints de SS primaire ou secondaire lorsque l'on comparait avec les sujets contrôles. Les résultats de cette étude corroborent ainsi l'idée suivant laquelle l'état parodontal des patients atteints de SS ne différe pas de celui des sujets en bonne santé du même âge et du même sexe. [source] NAAG peptidase inhibitor increases dialysate NAAG and reduces glutamate, aspartate and GABA levels in the dorsal hippocampus following fluid percussion injury in the ratJOURNAL OF NEUROCHEMISTRY, Issue 4 2006Chunlong Zhong Abstract Traumatic brain injury (TBI) produces a rapid and excessive elevation in extracellular glutamate that induces excitotoxic brain cell death. The peptide neurotransmitter N -acetylaspartylglutamate (NAAG) is reported to suppress neurotransmitter release through selective activation of presynaptic group II metabotropic glutamate receptors. Therefore, strategies to elevate levels of NAAG following brain injury could reduce excessive glutamate release associated with TBI. We hypothesized that the NAAG peptidase inhibitor, ZJ-43 would elevate extracellular NAAG levels and reduce extracellular levels of amino acid neurotransmitters following TBI by a group II metabotropic glutamate receptor (mGluR)-mediated mechanism. Dialysate levels of NAAG, glutamate, aspartate and GABA from the dorsal hippocampus were elevated after TBI as measured by in vivo microdialysis. Dialysate levels of NAAG were higher and remained elevated in the ZJ-43 treated group (50 mg/kg, i.p.) compared with control. ZJ-43 treatment also reduced the rise of dialysate glutamate, aspartate, and GABA levels. Co-administration of the group II mGluR antagonist, LY341495 (1 mg/kg, i.p.) partially blocked the effects of ZJ-43 on dialysate glutamate and GABA, suggesting that NAAG effects are mediated through mGluR activation. The results are consistent with the hypothesis that inhibition of NAAG peptidase may reduce excitotoxic events associated with TBI. [source] A novel prohormone processing site in Aplysia californica: the Leu,Leu ruleJOURNAL OF NEUROCHEMISTRY, Issue 6 2002Amanda B. Hummon Abstract Neuropeptides are a complex set of signaling molecules produced through enzymatic cleavages from longer prohormone sequences. The most common cleavage sites in prohormones are basic amino acid residues; however, processing is observed at non-basic sites. Cleavage at Leu,Leu sequences has been observed in three Aplysia californica prohormones. To further investigate this unusual event, native and non-native synthetic peptides containing Leu,Leu residues are incubated with homogenates of Aplysia californica ganglia and the resulting products monitored with MALDI MS. Cleavage near and between Leu,Leu residues is observed in the abdominal and buccal ganglia homogenates, confirming the presence of an unidentified peptidase. In addition, fractions from an HPLC separation of buccal ganglia homogenates also produce cleavages at Leu,Leu residues. Products resulting from cleavage at Leu,Leu sites are observed and are produced in larger amounts in acidic and neutral pH ranges, and cleavage is inhibited by the addition of EDTA, suggesting a metal is required for activity. [source] Purification and characterization of an endopeptidase that has an important role in the carboxyl terminal processing of antihypertensive peptides in Lactobacillus helveticus CM4LETTERS IN APPLIED MICROBIOLOGY, Issue 4 2004K. Ueno Abstract Aims:, To purify and characterize a peptidase that can catalyse C-terminal processing of antihypertensive peptide from Lactobacillus helveticus CM4. Methods and Results:, An endopeptidase which seems to process the carboxyl terminal end of two antihypertensive peptides, Val-Pro-Pro and Ile-Pro-Pro, was purified from Lactobacillus helveticus CM4 by four stages of column chromatography, using synthetic pro-peptide as a substrate. The molecular weight of the purified enzyme was estimated to be 67 000 by SEPHACRYL S-200 and 70 000 by SDS-PAGE analysis. The purified enzyme generated: (i) Val-Pro-Pro from Val-Pro-Pro-Phe-Leu and Val-Pro-Pro-Phe-Leu-Gln-Pro, and (ii) Ile-Pro-Pro from Ile-Pro-Pro-Leu-Thr and Ile-Pro-Pro-Leu-Thr-Gln-Thr, but theses peptides could not be generated from Val-Pro-Pro-Phe, Val-Pro-Pro-Phe-Leu-Gln, Ile-Pro-Pro-Leu and Ile-Pro-Pro-Leu-Thr-Gln. Part of the amino terminal sequence of the purified enzyme had homology to a previously reported pepO gene product. Conclusion:, These results suggest that the purified endopeptidase isolated in this study have an important role in the carboxyl terminal processing of two antihypertensive peptides in Lact. helveticus CM4. [source] Simple enzymatic procedure for l -carnosine synthesis: whole-cell biocatalysis and efficient biocatalyst recyclingMICROBIAL BIOTECHNOLOGY, Issue 1 2010Jan Heyland Summary , -Peptides and their derivates are usually stable to proteolysis and have an increased half-life compared with , -peptides. Recently, , -aminopeptidases were described as a new enzyme class that enabled the enzymatic degradation and formation of , -peptides. As an alternative to the existing chemical synthesis routes, the aim of the present work was to develop a whole-cell biocatalyst for the synthesis and production of , -peptides using this enzymatic activity. For the optimization of the reaction system we chose the commercially relevant ,,, -dipeptide l -carnosine (, -alanine- l -histidine) as model product. We were able to show that different recombinant yeast and bacteria strains, which overexpress a , -peptidase, could be used directly as whole-cell biocatalysts for the synthesis of l -carnosine. By optimizing relevant reaction conditions for the best-performing recombinant Escherichia coli strain, such as pH and substrate concentrations, we obtained high l -carnosine yields of up to 71%. Long-time as well as biocatalyst recycling experiments indicated a high stability of the developed biocatalyst for at least five repeated batches. Application of the recombinant E. coli in a fed-batch process enabled the accumulation of l -carnosine to a concentration of 3.7 g l,1. [source] Comparative enzymology of native and recombinant house dust mite allergen Der p 1ALLERGY, Issue 3 2009J. Zhang Background:, The cysteine peptidase activity of group 1 house dust mite allergens is important for their allergenicity and may offer new therapeutic targets for allergy treatment. Hitherto, the design of specific inhibitors has been impeded because the availability of pure, fully active allergens has limited the implementation of drug screening campaigns. Similarly, investigation of the mechanisms by which peptidase allergens promote sensitization has also been restricted. Our aim was to compare the enzymology of recombinant and native forms of Der p 1 to establish if an easily expressed recombinant form of Der p 1 could be used as a drug discovery tool. Methods:, Enzymatic activity of natural and recombinant Der p 1 was compared fluorimetrically using a novel specific substrate (ADZ 50,059) and a novel specific active site titrant (ADZ 50,000). The effect of recombinant Der p 1 prodomain on the catalytic activity of both Der p 1 preparations was also examined. Results:, Although differing substantially in molecular weight, the enzymological properties of recombinant and native Der p 1 were indistinguishable. Our data show clearly by experiment that, in contrast to some suggestions, Der p 1 is not an enzyme of bifunctional mechanism. Conclusion:, The catalytic activity of Der p 1 is tolerant of glycosylation differences that occur at N150 when the protein is expressed in Pichia pastoris. This suggests that this recombinant protein may be suitable for drug design studies and in the elucidation of how peptidase activity promotes sensitization to peptidase and nonpeptidase bystander allergens. [source] Investigating lipoprotein biogenesis and function in the model Gram-positive bacterium Streptomyces coelicolorMOLECULAR MICROBIOLOGY, Issue 4 2010Benjamin J. Thompson Summary Lipoproteins are a distinct class of bacterial membrane proteins that are translocated across the cytoplasmic membrane primarily by the Sec general secretory pathway and then lipidated on a conserved cysteine by the enzyme lipoprotein diacylglycerol transferase (Lgt). The signal peptide is cleaved by lipoprotein signal peptidase (Lsp) to leave the lipid-modified cysteine at the N-terminus of the mature lipoprotein. In all Gram-positive bacteria tested to date this pathway is non-essential and the lipid attaches the protein to the outer leaflet of the cytoplasmic membrane. Here we identify lipoproteins in the model Gram-positive bacterium Streptomyces coelicolor using bioinformatics coupled with proteomic and downstream analysis. We report that Streptomyces species translocate large numbers of lipoproteins out via the Tat (twin arginine translocase) pathway and we present evidence that lipoprotein biogenesis might be an essential pathway in S. coelicolor. This is the first analysis of lipoproteins and lipoprotein biogenesis in Streptomyces and provides the first evidence that lipoprotein biogenesis could be essential in a Gram-positive bacterium. This report also provides the first experimental evidence that Tat plays a major role in the translocation of lipoproteins in a specific bacterium. [source] The vanG glycopeptide resistance operon from Enterococcus faecalis revisitedMOLECULAR MICROBIOLOGY, Issue 3 2003Florence Depardieu Summary Acquired VanG-type resistance to vancomycin (MIC = 16 µg ml,1) but susceptibility to teicoplanin in Enterococcus faecalis BM4518 and WCH9 is due to the inducible synthesis of peptidoglycan precursors ending in d -alanine- d -serine. The vanG cluster, assigned to a chromosomal location, was composed of genes recruited from various van operons. The 3, end encoded VanG, a d -Ala:d -Ser ligase, VanXYG, a putative bifunctional d,d -peptidase and VanTG, a serine racemase: VanG and VanTG were implicated in the synthesis of d -Ala:d -Ser as in VanC- and VanE-type strains. Upstream from the structural genes for these proteins were vanWG with unknown function and vanYG containing a frameshift mutation which resulted in premature termination of the encoded protein and accounted for the lack of UDP-MurNAc-tetrapeptide in the cytoplasm. Without the frameshift mutation, VanYG had homology with Zn2+ dependent d,d -carboxypeptidases. The 5, end of the gene cluster contained three genes vanUG, vanRG and vanSG encoding a putative regulatory system, which were co-transcribed constitutively from the PYG promoter, whereas transcription of vanYG,WG,G,XYG,TG was inducible and initiated from the PYG promoter. Transfer of VanG-type glycopeptide resistance to E. faecalis JH2-2 was associated with the movement, from chromosome to chromosome, of genetic elements of c. 240 kb carrying also ermB -encoded erythromycin resistance. Sequence determination of the flanking regions of the vanG cluster in donor and transconjugants revealed the same 4 bp direct repeats and 22 bp imperfect inverted repeats that delineated the large element. [source] Purification and partial characterization of a dipeptidyl peptidase from Prevotella intermediaMOLECULAR ORAL MICROBIOLOGY, Issue 3 2003Y. Shibata A peptidase hydrolyzed X-Pro- p -nitroanilide was purified from the cell extract of Prevotella intermedia ATCC 25611 by ion-exchange chromatography and hydrophobic interaction chromatography. The purified enzyme exhibited a molecular size of 74 kDa from sodium dodecyl sulfate-polyacrylamide gel electrophoresis and the maximum enzyme activity was found between pH 7.0 and pH 7.5. This peptidase was a serine enzyme and hydrolyzed Lys-Pro- p -nitroanilide, Arg-Pro- p -nitroanilide, and Ala-Pro- p -nitroanilide, but Lys-Ala- p -nitroanilide was not split. The enzyme may be classified as a dipeptidyl peptidase IV. [source] Population changes in Phytophthora infestans in Taiwan associated with the appearance of resistance to metalaxyl,PEST MANAGEMENT SCIENCE (FORMERLY: PESTICIDE SCIENCE), Issue 9 2002Kenneth L Deahl Abstract In recent years, late blight, caused by Phytophthora infestans (Mont) De Bary, has increased in severity in many parts of the world, and this has been associated with migrations which have introduced new, arguably more aggressive, populations of the pathogen. In Taiwan, late blight has been endemic on outdoor tomato crops grown in the highlands since the early 1900s, but recent epidemics have been more damaging. To ascertain the present status of the Taiwanese population of P infestans, 139 isolates of the pathogen collected and maintained by the Asian Vegetable Research and Development Center (AVRDC) were characterized using mating type, metalaxyl sensitivity, allozyme genotype, mitochondrial haplotype and RFLP fingerprinting. Up to 1997, all isolates were found to belong to the old clonal lineage of P infestans (US-1 and variants), but in isolates from 1998 a new genotype appeared, and by 2000 this had apparently completely displaced the old population. This new genotype was an A1 mating type and has the dilocus allozyme genotype 100/100/111, 100/100 for the loci coding for glucose-6-phosphate isomerase and peptidase, respectively. These characters, together with RG57 fingerprinting, indicated that these isolates belonged to the US-11 clonal lineage, a minority (11%) being a previously unreported variant of US-11. Whereas metalaxyl-resistant isolates were not detected in the old population, 96% of the new genotypes proved resistant, with the remainder being intermediate in sensitivity. It may be inferred from this sudden, marked change in the characteristics of the Taiwanese P infestans that a new population of the pathogen was introduced around 1997,98 and that this may well have already been metalaxyl-resistant when it arrived, although a role for in situ selection cannot be excluded. © 2002 Society of Chemical Industry [source] | |||||||||||||||||||