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Potential Substrates (potential + substrate)
Selected AbstractsChemoenzymatic Synthesis of Branched Oligo- and Polysaccharides as Potential Substrates for Starch Active Enzymes.CHEMINFORM, Issue 9 2004Lionel Greffe No abstract is available for this article. [source] Purification, crystallization and preliminary X-ray analysis of cytochrome P450 219A1 from Novosphingobium aromaticivorans DSM 12444ACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 4 2009Chuan Hong Cytochrome P450 enzymes catalyze a variety of reactions and are widely distributed in living organisms. In recent studies, the first members of five new families of cytochrome P450 enzymes have been identified, including cytochrome P450 219A1 (CYP219A1) from Novosphingobium aromaticivorans DSM 12444. It has also been reported that isolongifolen-9-one (C15H22O), a sesquiterpenoid ketone derivative, is a potential substrate for CYP219A1, inducing a ,95% shift of the haem spin state to high spin upon binding. The CYP219A1 protein has been crystallized and single crystals have been studied by X-ray crystallography. Diffraction data were collected to 2.4,Å resolution. The crystals belonged to space group P6, with unit-cell parameters a = 93.1, b = 93.1, c = 98.0,Å. Preliminary X-ray diffraction data analysis revealed that the asymmetric unit contained one protein molecule. [source] Potential of agroindustrial waste from olive oil industry for fuel ethanol productionBIOTECHNOLOGY JOURNAL, Issue 12 2007Tania I. Georgieva Abstract Olive pulp (OP) is a highly polluting semi-solid residue generated from the two-stage extraction processing of olives and is a major environmental issue in Southern Europe, where 80% of the world olive oil is produced. At present, OP is either discarded to the environment or combusted with low calorific value. In this work, utilization of OP as a potential substrate for production of bioethanol was studied. Enzymatic hydrolysis and subsequent glucose fermentation by baker's yeast were evaluated for OP from 10% to 30% dry matter (i.e., undiluted). Enzymatic hydrolysis resulted in an increase in glucose concentration by 75%, giving final glucose yields near 70%. Fermentation of undiluted OP hydrolysate (OPH) resulted in the maximum ethanol produced (11.2 g/L) with productivity of 2.1 g/L/h. Ethanol yields were similar for all tested OPH concentrations and were in the range of 0.49-0.51 g/g. Results showed that yeast could effectively ferment OPH even without nutrient addition, revealing the tolerance of yeast to OP toxicity. Because of low xylan (12.4%) and glucan (16%) content in OP, this specific type of OP is not a suitable material for producing only ethanol and thus, bioethanol production should be integrated with production of other value-added products. [source] Microbiological investigation of methane- and hydrocarbon-discharging mud volcanoes in the Carpathian Mountains, RomaniaENVIRONMENTAL MICROBIOLOGY, Issue 4 2006Karine Alain Summary Paclele Mici is a terrestrial mud volcano field located in the Carpathian Mountains (Romania), where thermal alteration of sedimentary organic compounds leads to methane, higher hydrocarbons and other petroleum compounds that are continuously released into the environment. The hydrocarbons represent potential substrates for microorganisms. We studied lipid biomarkers, stable isotope ratios, the effect of substrate (methane, other organic compounds) addition and 16S rRNA genes to gain insights into the hitherto unknown microbial community at this site. Quantitative real-time polymerase chain reaction analysis demonstrated that bacteria were much more abundant than archaea. Phylogenetic analyses of 16S rDNA clone sequences indicated the presence of bacterial and archaeal lineages generally associated with the methane cycle (methanogens, aerobic and anaerobic methanotrophs), the sulfur cycle (sulfate reducers), and groups linked to the anaerobic degradation of alkanes or aromatic hydrocarbons. The presence of sulfate reducers, methanogens and methanotrophs in this habitat was also confirmed by concurrent surveys of lipid biomarkers and their isotopic signatures. Incubation experiments with several common and complex substrates revealed the potential of the indigenous microbial community for sulfate reduction, methanogenesis and aerobic methanotrophy. Additionally, consistently to the detection of methane-oxidizing archaea (ANME) and 13C-depleted archaeal lipids, a weak but significant activity of anaerobic methane oxidation was measured by radiotracer techniques and in vitro. This survey is the first to report the presence and activity of ANME in a terrestrial environment. [source] Novel diadenosine polyphosphate analogs with oxymethylene bridges replacing oxygen in the polyphosphate chainFEBS JOURNAL, Issue 6 2009Potential substrates and/or inhibitors of Ap4A hydrolases Dinucleoside polyphosphates (NpnN,s; where N and N, are nucleosides and n = 3,6 phosphate residues) are naturally occurring compounds that may act as signaling molecules. One of the most successful approaches to understand their biological functions has been through the use of NpnN, analogs. Here, we present the results of studies using novel diadenosine polyphosphate analogs, with an oxymethylene group replacing one or two bridging oxygen(s) in the polyphosphate chain. These have been tested as potential substrates and/or inhibitors of the symmetrically acting Ap4A hydrolase [bis(5,-nucleosyl)-tetraphosphatase (symmetrical); EC 3.6.1.41] from E. coli and of two asymmetrically acting Ap4A hydrolases [bis(5,-nucleosyl)-tetraphosphatase (asymmetrical); EC 3.6.1.17] from humans and narrow-leaved lupin. The six chemically synthesized analogs were: ApCH2OpOCH2pA (1), ApOCH2pCH2OpA (2), ApOpCH2OpOpA (3), ApCH2OpOpOCH2pA (4), ApOCH2pOpCH2OpA (5) and ApOpOCH2pCH2OpOpA (6). The eukaryotic asymmetrical Ap4A hydrolases degrade two compounds, 3 and 5, as anticipated in their design. Analog 3 was cleaved to AMP (pA) and ,,,-methyleneoxy-ATP (pOCH2pOpA), whereas hydrolysis of analog 5 gave two molecules of ,,,-oxymethylene ADP (pCH2OpA). The relative rates of hydrolysis of these analogs were estimated. Some of the novel nucleotides were moderately good inhibitors of the asymmetrical hydrolases, having Ki values within the range of the Km for Ap4A. By contrast, none of the six analogs were good substrates or inhibitors of the bacterial symmetrical Ap4A hydrolase. [source] Characterization of a novel silkworm (Bombyx mori) phenol UDP-glucosyltransferaseFEBS JOURNAL, Issue 3 2002Teresa Luque Sugar conjugation is a major pathway for the inactivation and excretion of both endogenous and exogenous compounds. We report here the molecular cloning and functional characterization of a phenol UDP-glucosyltransferase (UGT) from the silkworm, Bombyx mori, which was named BmUGT1. The complete cDNA clone is 1.6 kb, and the gene is expressed in several tissues of fifth-instar larvae, including fat body, midgut, integument, testis, silk gland and haemocytes. The predicted protein comprises 520 amino acids and has ,,30% overall amino-acid identity with other members of the UGT family. The most conserved region of the protein is the C-terminal half, which has been implicated in binding the UDP-sugar. BmUGT1 was expressed in insect cells using the baculovirus expression system, and a range of compounds belonging to diverse chemical groups were assessed as potential substrates for the enzyme. The expressed enzyme had a wide substrate specificity, showing activity with flavonoids, coumarins, terpenoids and simple phenols. These results support a role for the enzyme in detoxication processes, such as minimizing the harmful effects of ingested plant allelochemicals. This work represents the first instance where an insect ugt gene has been associated with a specific enzyme activity. [source] The noncoding RNA, miR-126, suppresses the growth of neoplastic cells by targeting phosphatidylinositol 3-kinase signaling and is frequently lost in colon cancersGENES, CHROMOSOMES AND CANCER, Issue 11 2008Chunguang Guo MicroRNAs (miRNA/miR) are a class of small noncoding RNAs implicated in the pathogenesis of various malignancies. In the current study, using micro(RNA) arrays, we found a ubiquitous loss of miR-126 expression in colon cancer lines when compared to normal human colon epithelia. Reconstitution of miR-126 in colon cancer cells resulted in a significant growth reduction as evidenced in clonogenic assays. A search for miR-126 gene targets revealed p85,, a regulatory subunit involved in stabilizing and propagating the phosphatidylinositol 3-kinase (PI3K) signal, as one of the potential substrates. Restoration of miR-126 in cancer cells induced a ,3-fold reduction in p85, protein levels, with no concomitant change in p85,, a gene that is functionally related to p85, but not a supposed target of miR-126. Additionally, using reporter constructs, we show that the p85,-3, untranslated region is directly targeted by miR-126. Furthermore, this miR-126 mediated reduction of p85, was accompanied by a substantial reduction in phosphorylated AKT levels in the cancer cells, suggesting an impairment in PI3K signaling. Finally, in a panel of matched normal colon and primary colon tumors, each of the tumors demonstrated miR-126 down-regulation together with an increase in the p85, protein level. Taken together, we propose that miR-126 regulates PI3K signaling partly by targeting p85,, and that the loss of miR-126 may provide a selective growth advantage during colon carcinogenesis. © 2008 Wiley-Liss, Inc. [source] Characterization of the methylation patterns of MS4A2 in atopic cases and controlsALLERGY, Issue 3 2010M. A. R. Ferreira To cite this article: Ferreira MAR, Oates NA, van Vliet J, Zhao ZZ, Ehrich M, Martin NG, Montgomery GW, Whitelaw E, Duffy DL. Characterization of the methylation patterns of MS4A2 in atopic cases and controls. Allergy 2010; 65: 333,337. Abstract Background:, It is largely unknown whether epigenetic modifications of key genes may contribute to the reported maternal effects in atopy. The aim of this study was to characterize the methylation patterns of the membrane-spanning 4-domains, subfamily A, member 2 gene (MS4A2) (,-chain of the IgE high-affinity receptor), a key gene in the allergic cascade. Methods:, Mass spectrometry and bisulphite sequencing were used to measure the methylation of two potential substrates for epigenetic regulation of MS4A2, namely a predicted promoter and a CpG-rich AluSp repeat. Methylation was measured in DNA extracted from peripheral blood lymphocytes of 38 atopic cases and 37 controls. Cases were positive for atopy, asthma, bronchial hyper-responsiveness and had high IgE levels. Both parents of eight atopic cases were also tested. Results:, The AluSp element was highly methylated across all individuals (mean 0.92, range 0.87,0.94), a pattern inconsistent with classical imprinting. Variation in methylation at this locus was not associated with age, sex, daily steroid use or atopic status, and there were no differences in methylation between mothers and fathers of atopic cases. Bisulphite sequencing analysis of the promoter region showed that it was also not imprinted, and there was no evidence for allele-specific methylation, but we were unable to test for association with atopy status. Conclusions:, Methylation levels at the AluSp repeat analysed in MS4A2 were inconsistent with classical imprinting mechanisms and did not associate with atopy status. The promoter region was less methylated but further analysis of this region in larger cohorts is warranted to investigate its role in allergic disease. [source] Angiotensin I-converting enzyme and potential substrates in human testis and testicular tumoursAPMIS, Issue 1 2003Review article The angiotensin I-converting enzyme (ACE, kininase II, CD143) shows a broad specificity for various oligopeptides. Besides the well-known conversion of angiotensin I to II, ACE degrades efficiently kinins and the tetrapeptide AcSDKP (goralatide) and thus equally participates in the renin-angiotensin system, the kallikrein-kinin system, and the regulation of stem cell proliferation. In the mammalian testis, ACE occurs in two isoforms. The testicular isoform (tACE) is exclusively expressed during spermatogenesis and is generally thought to represent the germ cell-specific isozyme. However, we have previously demonstrated that, in addition to tACE, the somatic isoform (sACE) is also present in human germ cells. Similar to other oncofoetal markers, sACE exhibits a transient expression during foetal germ cell development and appears to be a constant feature of intratubular germ cell neoplasm, the so-called carcinoma-in-situ (CIS) and, in particular, of classic seminoma. This demands the existence of specific paracrine functions during male germ cell differentiation and development of male germ cell tumours, which are mediated by either of the two ACE isoforms. Considering the complexity of current data about ACE, a logical connection is required between () the precise localisation of ACE isoforms, (I) the local access to potential substrates and (II) functional data obtained by knockout mice models. The present article summarises the current knowledge about ACE and its potential substrates with special emphasis on the differentiation-restricted ACE expression during human spermatogenesis and prespermatogenesis, the latter being closely linked to the pathogenesis of human germ cell tumours. [source] Emergence of protein kinase CK2 as a key target in cancer therapyBIOFACTORS, Issue 3 2010Janeen H. Trembley Abstract Protein kinase CK2, a protein serine/threonine kinase, plays a global role in activities related to cell growth, cell death, and cell survival. CK2 has a large number of potential substrates localized in diverse locations in the cell including, for example, NF-,B as an important downstream target of the kinase. In addition to its involvement in cell growth and proliferation it is also a potent suppressor of apoptosis, raising its key importance in cancer cell phenotype. CK2 interacts with diverse pathways which illustrates the breadth of its impact on the cellular machinery of both cell growth and cell death giving it the status of a "master regulator" in the cell. With respect to cancer, CK2 has been found to be dysregulated in all cancers examined demonstrating increased protein expression levels and nuclear localization in cancer cells compared with their normal counterparts. We originally proposed CK2 as a potentially important target for cancer therapy. Given the ubiquitous and essential for cell survival nature of the kinase, an important consideration would be to target it specifically in cancer cells while sparing normal cells. Towards that end, our design of a tenascin based sub-50 nm (i.e., less than 50 nm size) nanocapsule in which an anti-CK2 therapeutic agent can be packaged is highly promising because this formulation can specifically deliver the cargo intracellularly to the cancer cells in vivo. Thus, appropriate strategies to target CK2 especially by molecular approaches may lead to a highly feasible and effective approach to eradication of a given cancer. [source] | ||||||||||||||||