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Decarboxylase Activity (decarboxylase + activity)

Distribution by Scientific Domains

Life Sciences	38%
Medical Sciences	30%
Chemistry	30%

Kinds of Decarboxylase Activity

ornithine decarboxylase activity

Selected Abstracts

The Influence of Lactobacillus brevis on Ornithine Decarboxylase Activity and Polyamine Profiles in Helicobacter pylori -Infected Gastric Mucosa

HELICOBACTER, Issue 2 2004
Michele Linsalata
ABSTRACT Background., Functional probiotics may prevent Helicobacter pylori infection, and some evidence suggests that they also possess antitumor properties. Lactobacillus brevis (CD2) is a functional Lactobacillus strain with peculiar biochemical features, essentially related to the activity of arginine deiminase. This enzyme catalyzes the catabolism of arginine and affects the biosynthesis of polyamines (putrescine, spermidine, and spermine). Polyamines are polycations found in high concentrations in both normal and neoplastic cells. Our aims were: 1, to assess whether oral administration of L. brevis (CD2) affects H. pylori survival in the human gastric mucosa; 2, to evaluate the effects of L. brevis (CD2) on polyamine biosynthesis in gastric biopsies from H. pylori- positive patients. Materials and Methods., For 3 weeks before endoscopy, 22 H. pylori- positive dyspeptic patients randomly received (ratio 1 : 1) high oral doses of L. brevis (CD2) or placebo. Before and after treatment, H. pylori infection was determined by urea breath test (UBT). In gastric biopsies, ornithine decarboxylase activity and polyamine levels were, respectively, evaluated by a radiometric technique and high-pressure liquid chromatography (HPLC). Results.,L. brevis (CD2) treatment did not eradicate H. pylori. However, a reduction in the UBT delta values occurred, suggesting a decrease in intragastric bacterial load. Significantly, L. brevis (CD2) induced a decrease in gastric ornithine decarboxylase activity and polyamine levels. Conclusions., Our data support the hypothesis that L. brevis (CD2) treatment decreases H. pylori colonization, thus reducing polyamine biosynthesis. Alternatively, the arginine deiminase activity following L. brevis (CD2) administration might cause arginine deficiency, preventing polyamine generation from gastric cells. [source]

Tyr235 of human cytosolic phosphoenolpyruvate carboxykinase influences catalysis through an anion,quadrupole interaction with phosphoenolpyruvate carboxylate

FEBS JOURNAL, Issue 23 2008
Lakshmi Dharmarajan
Tyr235 of GTP-dependent phosphoenolpyruvate (PEP) carboxykinase is a fully invariant residue. The aromatic ring of this residue establishes an energetically favorable weak anion,quadrupole interaction with PEP carboxylate. The role of Tyr235 in catalysis was investigated via kinetic analysis of site-directed mutagenesis-derived variants. The Y235F change lowered the apparent Km for PEP by about six-fold, raised the apparent Km for Mn2+ by about 70-fold, and decreased oxaloacetate (OAA)-forming activity by about 10-fold. These effects were due to an enhanced anion,quadrupole interaction between the aromatic side chain at position 235, which now lacked a hydroxyl group, and PEP carboxylate, which probably increased the distance between PEP and Mn2+ and consequently affected the phosphoryl transfer step and overall catalysis. For the Y235A and Y235S changes, an elimination of the favorable edge-on interaction increased the apparent Km for PEP by four- and six-fold, respectively, and the apparent Km for Mn2+ by eight- and six-fold, respectively. The pyruvate kinase-like activity, representing the PEP dephosphorylation step of the OAA-forming reaction, was affected by the substitutions in a similar way to the complete reaction. These observations indicate that the aromatic ring of Tyr235 helps to position PEP in the active site and the hydroxyl group allows an optimal PEP,Mn2+ distance for efficient phosphoryl transfer and overall catalysis. The Y235A and Y235S changes drastically reduced the PEP-forming and OAA decarboxylase activities, probably due to the elimination of the stabilizing interaction between Tyr235 and the respective products, PEP and pyruvate. [source]

Mutation of residues in the coenzyme binding pocket of Dopa decarboxylase

FEBS JOURNAL, Issue 10 2001
Effects on catalytic properties
Residues D271, H192, H302 and N300 of l -3,4-dihydroxyphenylalanine decarboxylase (DDC), a homodimeric pyridoxal 5,-phosphate (PLP) enzyme, were mutated in order to acquire information on the catalytic mechanism. These residues are potential participants in catalysis because they belong to the common PLP-binding structural motif of group I, II and III decarboxylases and other PLP enzymes, and because they are among the putative active-site residues of structural modelled rat liver DDC. The spectroscopic features of the D271E, H192Q, H302Q and N300A mutants as well as their dissociation constants for PLP suggest that substitution of each of these residues causes alteration of the state of the bound coenzyme molecule and of the conformation of aromatic amino acids, possibly in the vicinity of the active site. This supports, but does not prove, the possibility that these residues are located in the coenzyme-binding cleft. Interestingly, mutation of each residue generates an oxidative decarboxylase activity towards l -3,4-dihydroxyphenylalanine (l -Dopa), not inherent in the wild-type in aerobiosis, and reduces the nonoxidative decarboxylase activity of l -Dopa from 3- to 390-fold. The partition ratio between oxidative and nonoxidative decarboxylation ranges from 5.7 × 10,4 for N300A mutant to 946 × 10,4 for H302Q mutant. Unlike wild-type enzyme, the mutants catalyse these two reactions to the same extent either in the presence or absence of O2. In addition, all four mutants exhibit an extremely low level of the oxidative deaminase activity towards serotonin with respect to wild-type. All these findings demonstrate that although D271, H192, H302 and N300 are not essential for catalysis, mutation of these residues alters the nature of catalysis. A possible relationship among the integrity of the PLP cleft, the productive binding of O2 and the transition to a closed conformational state of DDC is discussed. [source]

The Influence of Lactobacillus brevis on Ornithine Decarboxylase Activity and Polyamine Profiles in Helicobacter pylori -Infected Gastric Mucosa

Biogenic amine production by lactic acid bacteria isolated from cider

LETTERS IN APPLIED MICROBIOLOGY, Issue 5 2007
G. Garai
Abstract Aims:, To study the occurrence of histidine, tyrosine and ornithine decarboxylase activity in lactic acid bacteria (LAB) isolated from natural ciders and to examine their potential to produce detrimental levels of biogenic amines. Methods and Results:, The presence of biogenic amines in a decarboxylase synthetic broth and in cider was determined by reversed-phase high-performance liquid chromatography (RP-HPLC). Among the 54 LAB strains tested, six (five lactobacilli and one oenococci) were biogenic amine producers in both media. Histamine and tyramine were the amines formed by the LAB strains investigated. Lactobacillus diolivorans were the most intensive histamine producers. This species together with Lactobacillus collinoides and Oenococcus oeni also seemed to produce tyramine. No ability to form histamine, tyramine or putrescine by Pediococus parvulus was observed, although it is a known biogenic amine producer in wines and beers. Conclusions:, This study demonstrated that LAB microbiota growing in ciders had the ability to produce biogenic amines, particularly histamine and tyramine, and suggests that this capability might be strain-dependent rather than being related to a particular bacterial species. Significance and Impact of the Study:, Production of biogenic amines by food micro-organisms has continued to be the focus of intensive study because of their potential toxicity. The main goal was to identify the microbial species capable of producing these compounds in order to control their presence and metabolic activity in foods. [source]

Assessment of carcinogenic potential of repeated fish fried oil in mice

MOLECULAR CARCINOGENESIS, Issue 10 2006
Manoj K. Pandey
Abstract Our prior studies have shown that single topical treatment of repeated fish fried oil extract (RFFE), containing various polycyclic aromatic hydrocarbons (PAHs), to the dorsal epidermis of mice caused enhancement of DNA damage along with higher expression of p53 and p21WAF1 proteins and cell-cycle arrest. In the present study carcinogenic potential of repeated fish fried oil (RFFO) and RFFE was assessed. Single topical application of RFFO (100 µL/animal) and RFFE (100,500 µg/animal) to Swiss albino female mice resulted in significant induction (1.8- to 7.4-fold) of ornithine decarboxylase activity. Twice weekly topical application of methylcholanthrene (MCA) for 24 wk or single topical application of 7,12-dimethylbenzanthracene (DMBA) or RFFO or RFFE, as initiator followed by twice weekly application of 12-O-tetradecanoyl phorbol myristate acetate (TPA) as promoter for 24 wk, resulted in development of skin papillomas after 6, 7, 18, and 9 wk, respectively. The cumulative number of tumors in MCA, DMBA/TPA, RFFE (200 µg)/TPA, and RFFE (500 µg)/TPA groups were 276, 168, 34, and 58 after 24 wk while negligible or minimal initiating activity was noticed in RFFO/TPA group. No tumors were found in animals either given twice weekly topical application of RFFO or a single initiating dose of DMBA followed by twice weekly application of RFFO. Histopathology of skin of animals treated with RFFE/TPA showed marked proliferation of epidermal layers along with abnormal mitosis and multinucleated tumor appearance. Skin of animals in groups RFFO/TPA and DMBA/RFFO showed sloughing and regeneration of epidermal layers, oedema along with proliferation of fibroblasts. Histochemical localization of ,-glutamyl transpeptidase was found to be substantially higher in skin of mice treated with RFFO/TPA and RFFE/TPA. Animals treated with RFFO/TPA, DMBA/RFFO, and RFFE/TPA resulted in significant induction of cutaneous aryl hydrocarbon hydroxylase (AHH) (421,432%), ethoxyresorufin-O-deethylase (252,316%), and glutathione S-transferase (133,245%) activities. Animals treated with RFFO/TPA, DMBA/RFFO, and RFFE/TPA led to significant reduction in glutathione content (39,44%) with a concomitant increase in lipid peroxidation (254,492%). Animals treated with RFFO/TPA and RFFE/TPA led a significant decrease in catalase (43,69%) and superoxide dismutase (20,31%) activities while glutathione reductase activity was found to be diminished (23,51%) in RFFO, RFFO/TPA, DMBA/RFFO, and RFFE/TPA treated groups. These results suggest that RFFE possess skin tumor initiating activity and that it may have weak promoting activity as well, which may involve free radicals. © 2006 Wiley-Liss, Inc. [source]

Biosynthesis profile and endogenous titers of polyamines differ in totipotent and recalcitrant plant protoplasts

PHYSIOLOGIA PLANTARUM, Issue 1 2005
Anastasia K. Papadakis
The expression of totipotency in plant protoplasts is a complex developmental phenomenon and is affected by genetic and physiological factors. Polyamines (PAs) are known to be involved in a variety of growth and developmental processes in higher plants, as well as in adaptation to stresses. In this study, we present the homeostatic characteristics of the endogenous PA putrescine (Put), spermidine (Spd), and spermine (Spm) in totipotent (T) and non-totipotent (NT) tobacco protoplasts and in recalcitrant (R) grapevine protoplasts. T-tobacco protoplasts, with high division rates, have the highest level of endogenous PAs. In these protoplasts, the soluble-hydrolyzed fraction predominates and increases, and the insoluble-hydrolyzed fraction also increases, whereas soluble (S) PAs decrease rapidly during culture. The isolation process contributes to the increased Put levels, which are higher in freshly isolated NT-tobacco protoplasts than in T-protoplasts. During culture, total Put predominates over Spd and Spm, and the highest accumulation is found in T-protoplasts. Ornithine decarboxylase and arginase activities both increase in T-protoplasts, whereas arginine decarboxylase activity causes Put accumulation in NT-tobacco protoplasts. R-grapevine protoplasts show a different PA profile, mostly due to the lower PA content, the higher S-fraction, and the higher ratio of Spm to total PAs. The data suggest that the levels and metabolism of the intracellular PAs could be related to the expression of totipotency of plant protoplasts. [source]

Ornithine decarboxylase activity of L929 cells after exposure to continuous wave or 50 Hz modulated radiofrequency radiation,a replication study

BIOELECTROMAGNETICS, Issue 7 2007
A. Höytö
Abstract A replication study with some extensions was made to confirm enhancement of ornithine decarboxylase (ODC) activity in murine L929 fibroblasts after radiofrequency (RF) field exposure reported in earlier studies. L929 cells purchased from two cell banks were exposed for 2, 8, or 24 h to continuous wave or DAMPS (burst modulated at 50 Hz, with 33% duty cycle) signals at specific absorption rate (SAR) levels of 2.5 or 6.0 W/kg. Exposures were carried out in Crawford and waveguide chambers, at frequencies 835 and 872 MHz, respectively. The results did not confirm findings of previous studies reporting increased ODC activity in RF-exposed cells. When Crawford cell exposure system was used, ODC activity was either not affected (in the case of 8 or 24 h exposures) or decreased after 2 h exposure at the highest SAR level (6 W/kg). The decrease was most pronounced when cooling with air flow was not used, and is most likely related to increased temperature. The minor methodological differences (use of antibiotics, increased sensitivity of ODC assay) are not likely to explain the inconsistency of the findings of the present and previous studies. Different results were obtained in experiments with the waveguide system that involves more efficient temperature control. In this exposure system, ODC activity was increased after 8 h exposure at 6 W/kg. Further studies are warranted to explore whether this finding reflects a true non-thermal effect. The present study did not provide evidence for modulation-specific effects reported in earlier studies. Bioelectromagnetics 28:501,508, 2007. © 2007 Wiley-Liss, Inc. [source]

Treatment of Germinated Wheat to Increase Levels of GABA and IP6 Catalyzed by Endogenous Enzymes

BIOTECHNOLOGY PROGRESS, Issue 2 2005
Hiroyuki Nagaoka
We found that the levels of bioactive products from wheat can be increased dramatically by manipulating germination conditions and taking advantage of the activity of endogenous enzymes. The yield of phytic acid (IP6) from wheat germinated in the presence of high, controlled levels of dissolved oxygen (188 ± 28 mg/100 g wheat) was almost three times greater than that from wheat germinated with no supplemental oxygen (74 ± 10 mg/100 g wheat). The yield of ,-aminobutyric acid (GABA) from wheat germinated in the presence of uncontrolled levels of dissolved oxygen was 18 ± 3 times greater than that from nonsupplemented wheat (1 mg/100 g wheat). The concentration of GABA was much greater in wheat germ than in whole wheat, and the yield of GABA from wheat germ processed with supplemental water (163 ± 7 mg/100 g wheat germ) was notably greater than that from wheat germ processed with no supplemental water (100 ± 2 mg/100 g wheat germ). In contrast, IP6 was more concentrated in wheat bran, and the yield of IP6 from wheat bran processed with supplemental water (3100 ± 12 mg/100 g wheat bran) was notably higher than that from wheat bran processed with no supplemental water (2420 ± 13 mg/100 g wheat bran). We conclude that the large amount of GABA extracted from wheat germ is likely due to high glutamate decarboxylase activity and low aminotransferase activity and that the large amount of IP6 extracted from wheat bran is likely due to high levels of tyrosinase activity. Our findings indicate that bioactive molecules such as GABA and IP6 can be successfully mass-produced by taking advantage of endogenous enzymatic activities. [source]

Overexpression, purification, crystallization and preliminary structural studies of p -coumaric acid decarboxylase from Lactobacillus plantarum

ACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 4 2007
Blanca De Las Rivas
The substrate-inducible p -coumaric acid decarboxylase (PDC) from Lactobacillus plantarum has been overexpressed in Escherichia coli, purified and confirmed to possess decarboxylase activity. The recombinant His6 -tagged enzyme was crystallized using the hanging-drop vapour-diffusion method from a solution containing 20%(w/v) PEG 4000, 12%(w/v) 2-propanol, 0.2,M sodium acetate, 0.1,M Tris,HCl pH 8.0 with 0.1,M barium chloride as an additive. Diffraction data were collected in-house to 2.04,Å resolution. Crystals belonged to the tetragonal space group P43, with unit-cell parameters a = b = 43.15, c = 231.86,Å. The estimated Matthews coefficient was 2.36,Å3,Da,1, corresponding to 48% solvent content, which is consistent with the presence of two protein molecules in the asymmetric unit. The structure of PDC has been determined by the molecular-replacement method. Currently, the structure of PDC complexed with substrate analogues is in progress, with the aim of elucidating the structural basis of the catalytic mechanism. [source]

Catecholamine synthesis and metabolism in the central nervous system of mice lacking ,2 -adrenoceptor subtypes

BRITISH JOURNAL OF PHARMACOLOGY, Issue 3 2009
MA Vieira-Coelho
Background and purpose:, This study investigates the role of ,2 -adrenoceptor subtypes, ,2A, ,2B and ,2C, on catecholamine synthesis and catabolism in the central nervous system of mice. Experimental approach:, Activities of the main catecholamine synthetic and catabolic enzymes were determined in whole brains obtained from ,2A -, ,2B - and ,2C -adrenoceptor knockout (KO) and C56Bl\7 wild-type (WT) mice. Key results:, Although no significant differences were found in tyrosine hydroxylase activity and expression, brain tissue levels of 3,4-dihydroxyphenylalanine were threefold higher in ,2A - and ,2C -adrenoceptor KO mice. Brain tissue levels of dopamine and noradrenaline were significantly higher in ,2A and ,2CKOs compared with WT [WT: 2.8 ± 0.5, 1.1 ± 0.1; ,2AKO: 6.9 ± 0.7, 1.9 ± 0.1; ,2BKO: 2.3 ± 0.2, 1.0 ± 0.1; ,2CKO: 4.6 ± 0.8, 1.5 ± 0.2 nmol·(g tissue),1, for dopamine and noradrenaline respectively]. Aromatic L-amino acid decarboxylase activity was significantly higher in ,2A and ,2CKO [WT: 40 ± 1; ,2A: 77 ± 2; ,2B: 40 ± 1; ,2C: 50 ± 1, maximum velocity (Vmax) in nmol·(mg protein),1·h,1], but no significant differences were found in dopamine ,-hydroxylase. Of the catabolic enzymes, catechol- O -methyltransferase enzyme activity was significantly higher in all three ,2KO mice [WT: 2.0 ± 0.0; ,2A: 2.4 ± 0.1; ,2B: 2.2 ± 0.0; ,2C: 2.2 ± 0.0 nmol·(mg protein),1·h,1], but no significant differences were found in monoamine oxidase activity between all ,2KOs and WT mice. Conclusions and implications:, In mouse brain, deletion of ,2A - or ,2C -adrenoceptors increased cerebral aromatic L-amino acid decarboxylase activity and catecholamine tissue levels. Deletion of any ,2 -adrenoceptor subtypes resulted in increased activity of catechol- O -methyltransferase. Higher 3,4-dihydroxyphenylalanine tissue levels in ,2A and ,2CKO mice could be explained by increased 3,4-dihydroxyphenylalanine transport. [source]

Lipid peroxide-induced redox imbalance differentially mediates CaCo-2 cell proliferation and growth arrest

CELL PROLIFERATION, Issue 4 2002
Yudai Gotoh
Dietary oxidants like lipid hydroperoxides (LOOH) can perturb cellular glutathione/glutathione disulphide (GSH/GSSG) status and disrupt mucosal turnover. This study examines the effect of LOOH on GSH/GSSG balance and phase transitions in the human colon cancer CaCo-2 cell. LOOH at 1 or 5 µm were noncytotoxic, but disrupted cellular GSH/GSSG and stimulated proliferative activity at 6 h that paralleled increases in ornithine decarboxylase activity, thymidine incorporation, expression of cyclin D1/cyclin-dependent kinase 4, phosphorylation of retinoblastoma protein, and cell progression from G0/G1 to S. At 24 h, LOOH-induced sustained GSH/GSSG imbalance mediated growth arrest at G0/G1 that correlated with suppression of proliferative activity and enhanced oxidative DNA damage. LOOH-induced cell transitions were effectively blocked by N-acetylcysteine. Collectively, the study shows that subtoxic LOOH levels induce CaCo-2 GSH/GSSG imbalance that elicits time-dependent cell proliferation followed by growth arrest. These results provide insights into the mechanism of hydroperoxide-induced disruption of mucosal turnover with implications for understanding oxidant-mediated genesis of gut pathology. [source]

Structure and Mechanism of an Unusual Malonate Decarboxylase and Related Racemases

CHEMISTRY - A EUROPEAN JOURNAL, Issue 22 2008
Krzysztof Okrasa Dr.
Hole in one! The first structure of an arylmalonate decarboxylase (AMDase; see picture), which reveals the mechanism by which this unusual cofactor-independent enzyme catalyses the decarboxylation of ,-arylmalonates, is presented. Notably, an active site "dioxyanion hole" motif is utilised to stabilise a putative high-energy enediolate intermediate. Other AMDases are also characterised, along with a Glu-racemase that also possesses a dioxyanion hole and promiscuous malonate decarboxylase activity. [source]