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Deaminase Activity (deaminase + activity)
Kinds of Deaminase Activity Selected AbstractsMutation of residues in the coenzyme binding pocket of Dopa decarboxylaseFEBS JOURNAL, Issue 10 2001Effects 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] Cosmopolitan distribution of phlD -containing dicotyledonous crop-associated biocontrol pseudomonads of worldwide originFEMS MICROBIOLOGY ECOLOGY, Issue 2 2001Chunxia Wang Abstract In biocontrol fluorescent pseudomonads, phlD encodes a polyketide synthase required for the synthesis of the antifungal compound 2,4-diacetylphloroglucinol (Phl). Here, PCR-restriction fragment length polymorphism analysis was used to compare phlD alleles in 77 dicot-associated pseudomonads originating from various countries worldwide and 10 counterparts from a monocotyledonous host (wheat). The 16 restriction patterns obtained were mostly unrelated to geographic location or dicot host. Cluster analysis distinguished eight phlD clusters at a similarity level of 0.63. One cluster grouped 18 pseudomonads that produced also the antifungal polyketide pyoluteorin but could not assimilate D -galactose, D -galactonate lactone, D -sorbitol, L -arabinose, D -saccharate or D -xylose. These 18 pseudomonads, along with the eight pseudomonads from a second phlD cluster, were the only isolates that failed to deaminase 1-aminocyclopropane-1-carboxylate (ACC), a rare root growth promotion trait. Overall, assessment of phlD polymorphism, ACC deaminase activity and catabolic profiles pointed to a cosmopolitan distribution of Phl-producing biocontrol fluorescent pseudomonads of worldwide origin associated with dicotyledonous crop plants. [source] Characterization of ACC deaminase gene in Pseudomonas entomophila strain PS-PJH isolated from the rhizosphere soilJOURNAL OF BASIC MICROBIOLOGY, Issue 2 2010Seralathan Kamala-Kannan Abstract The enzyme 1-aminocyclopropane-1-carboxylate (ACC) deaminase cleaves the ethylene precursor ACC into ,-ketobutyrate and ammonia. The decreased level of ethylene allows the plant to be more resistant to a wide environmental stress including plant pathogens. In the present study, we characterized the ACC deaminase activity of a Pseudomonas entomophila strain PS-PJH isolated from the red pepper rhizosphere region of red pepper grown at Jinan, Korea. The isolate produced 23.8 ± 0.4 ,mol of ,-ketobutyrate/mg of protein/h during ACC deamination under in vitro conditions. Polymerase chain reaction for acdS gene showed that the isolated P. entomophila strain PS-PJH carry sequences similar to the known acdS genes. Results of the multiple sequence alignment revealed >99% identity (nucleotide and amino acid) with acdS gene of Pseudomonas putida strains AM15 and UW4. The isolated bacteria promoted 43.3 and 34.1% of growth in Raphanus sativus and Lactuca sativa plants, respectively. Based on the 16S,23S internal transcribed spacer region sequences, the isolate was identified as P. entomophila. To the best of our knowledge this is the first study to report the acdS gene in P. entomophila. (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Deamination of adenosine by extracts of Penicillium politans NRC-510JOURNAL OF BASIC MICROBIOLOGY, Issue 2 2005Ali M. Elshafei Prof. Cell-free extracts of nitrate-grown Penicillium politans NRC-510 could catalyze the hydrolytic deamination of adenosine to inosine maximally at pH 6.0 and 45 °C. However the same extracts could not catalyze the N-glycosidic bond cleavage of adenosine at pH 4.0, 6.0 and 8.0. Incubation of the extracts at 55 °C for 30 minutes caused about 31% loss in activity whereas incubation of the extracts at 60 °C for 15 minutes caused a complete loss of enzyme activity. Results indicated the absence of the involvement of sulfhydryl groups in the catalytic site of adenosine deaminase. The enzyme is inhibited by ethylene diamine tetraacetate indicating that adenosine deaminase is a metalloenzyme. MnCl2 and MgCl2 had a remarkable activating effect, whereas HgCl2, CaCl2 and ZnSO4 showed an inhibitory effect on enzyme activity. Dialyzing the extracts for 24 hours significantly increase deaminase activity by about 33%. The apparent Km value was calculated for adenosine and found to be 3.63 × 10,3M, which indicates high affinity of adenosine deaminase for its substrate adenosine. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] The anti-inflammatory modulatory role of Solidago chilensis Meyen in the murine model of the air pouchJOURNAL OF PHARMACY AND PHARMACOLOGY: AN INTERNATI ONAL JOURNAL OF PHARMACEUTICAL SCIENCE, Issue 4 2008Rafael Liz The aim of this study was to investigate the anti-inflammatory efficacy of an aqueous extract (AE), and its butanolic (BuOH) and aqueous residual (AR) fractions, derived from the rhizome of Solidago chilensis in inflammation caused by carrageenan in mice. Solidago chilensis Meyen rhizome was extracted using hot water at 90°C under infusion. The extract was filtered and lyophilized. Part of the aqueous extract was fractionated with n-BuOH, resulting in butanolic (BuOH) and aqueous residual (AR) fractions. Adult Swiss mice were used in the in-vivo experiments. We evaluated the effect of rhizome aqueous extract of Solidago chilensis and these two derived fractions on the inflammation induced by carrageenan in the mouse model of the air pouch. The aqueous extract and its derived fractions significantly inhibited leucocytes, neutrophils, exudation, myeloperoxidase and adenosine deaminase activity, as well as nitric oxide, interleukin-1 beta (IL-1,), neutrophil chemokine (KC) and tumour necrosis factor-alpha (TNF-,) levels (P < 0.05). Indometacin and dexamethasone inhibited all the studied inflammatory parameters (P < 0.01) with the exceptions that indometacin did not inhibit TNF-, levels and dexamethasone did not inhibit KC levels (P > 0.05). These results indicate that Solidago chilensis has a significant anti-inflammatory action on acute inflammatory responses and that its inhibitory activity may be due not only to the inhibition of pro-inflammatory mediators, but also to the inhibition of leucocyte infiltration. [source] Adenosine deaminase activity, trypsin inhibitory capacity and total antioxidant capacity in psoriasisJOURNAL OF THE EUROPEAN ACADEMY OF DERMATOLOGY & VENEREOLOGY, Issue 3 2010M Hashemi Abstract Background, Psoriasis is a chronic inflammatory skin disease characterized by pathological skin lesions because of various exogenous and endogenous factors and associated with a number of biochemical and immunological disturbances. Objective, The aim of the present study was to determine the level of adenosine deaminase activity, serum trypsin inhibitory capacity and total antioxidant capacity of plasma in psoriatic patients. Subjects and methods, The study was performed in controls (n = 46) and in psoriatic patients (n = 40). The patients were scored with PASI (psoriasis area and severity index). The serum ADA activity was determined using Aguisti and Galanti method and serum trypsin inhibitory capacity (sTIC) were measured by enzymatic assay. Besides, serum total antioxidant capacity was measured using ferric reducing ability of plasma. Results, The serum ADA activity of the psoriatic patients was found to be significantly higher (P < 0.001) than that of the healthy control. We also found that the trypsin inhibitory capacity was significantly higher in patients than in control group (P < 0.001). Total antioxidant capacity of plasma was significantly lower in psoriatic patients than in healthy controls (P = 0.025). There were no significant correlations among ADA, TAC and TIC. Conclusion, Serum ADA activity and sTIC were increased in psoriatic patients. In parallel, serum total anti-oxidant activity was decreased in these patients. [source] Decrease of adenosine deaminase activity and increase of the lipid peroxidation after acute methotrexate treatment in young rats: protective effects of grape seed extractCELL BIOCHEMISTRY AND FUNCTION, Issue 1 2010F. V. Pinheiro Abstract The methotrexate (MTX) is an anti-folate used to treat cancer and some inflammatory diseases. The efficacy of MTX is often limited by its severe toxicity. The present study was undertaken to determine whether Grape seed (Cabernet Sauvignon) extract (GSE) could ameliorate the MTX-induced oxidative injury and the effect on adenosine deaminase activity (ADA) in rats. The rats were pretreated with 50,mg/kg of GSE, i.p., prior to MTX administration (10,mg/kg, i.p.) with a second dose given 4,h and a third dose 16,h after MTX administration. Biochemical parameters were investigated 48,h after the last MTX administration. The administration of MTX increased thiobarbituric acid reactive species (TBARS) levels in hippocampus, kidney and liver, whereas induced a significant decreased in the ADA activity in the cerebral cortex, kidney and liver tissues. MTX administration significantly increased the activity of ALT(alanine aminotransferase) and urea levels and decreased uric acid levels in the serum. Urinary uric acid levels decreased in the MTX group when compared to those of the control group. The GSE along with MTX-administration significantly reversed these parameters toward to near normal. These results indicated that GSE could reduce hepatic and nephritic damage induced by MTX-treatment in young rats therefore having free radical scavenging. Copyright © 2009 John Wiley & Sons, Ltd. [source] | |||||||||||||