Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.5.1.4 (deaminase)
 5,113 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Half automated method for determining a L-leucinamide splitting enzymatic activity in human sera. In normal and pathological human sera, two distinct L-leucinamide splitting enzymatic activities have been demonstrated. One of them has an optimal activity at pH 9 (alcaline leucine amidase activity) and shows the most properties of a classic leucinaminopeptidase (E.C. 3.4.11.1). The other (neutral leucine amidase activity) has an optimal activity at pH : 7,5--7,8 and is not activated by Mg2+ ions. In the present work a semi-automated method permitting the determination of the "neutral leucine amidase activity" is presented. The mean of the reference values for normal human sera are established to 31,54 mUI/ml, and the upper normal limit is 48 mUI/ml. The neutral leucine amidase activity is studied in pathological sera comparatively with two other aminopeptidase activities : "alcaline leucine amidase activity", and "leucine-arylamidase". Our study shows that in pathological sera, the neutral leucine amidase activity" varies often without any correlation with those parameters.
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PMID:[Neutral leucinamidasic activity of human serum. Semiautomatic method of analysis]. 2 57

The effect of N10-formyl-H4folate on mitochondrial peptide chain initiation has been studied in isolated mitochondria of Saccharomyces cerevisiae. The addition of N10-formyl-H4-folate strongly stimulates the incorporation of amino acids into mitochondrial protein at both 6 and 15 mm Mg2+. Still higher stimulation (up to 10-fold) has been obtained in the production of de novo synthesized initial peptides, measured as peptidyl puromycin derivatives. The maximum effect is observed at 0.1 mM N10-formyl-H4folate. At 5 mM puromycin, the ratio formylated/unformylated peptides is 3, as shown by electrophoretic analysis. At 10 mM puromycin, the ratio is increased to more than 6. This is due to the presence of deformylase and amidohydrolase activities, which are more effective the longer the initial peptide is synthesized; at increasing puromycin concentrations, progressively shorter peptide chains are formed. Chemically synthesized fMet-puromycin and Met-puromycin are virtually stable when incubated with intact or frozen and thawed mitochondria. More careful kinetic analysis shows an early cessation of the initial peptide formation in the samples without N10-formyl-H4-folate. This indicates that the formylation of methionyl-tRNA formylatable species is an absolute requirement for mitochondrial peptide chain initiation.
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PMID:Dependence of mitochondrial protein synthesis initiation on formylation of the initiator methionyl-tRNAf. 32 47

Deamination of AMP in skeletal muscle sarcoplasmic reticulum followed by an increase in pH from 6,5 up to 8,0 leads in a liberation of part of Ca2+ from the SR vesicles. This effect is enhanced by K+, which activate the deamination, and is suppressed by Mg2+, which inhibit the reaction. The activating effect of AMP on Ca2+ efflux from the vesicles markedly decreases after AMP deaminase dissociation from the vesicles and is restored after reconstitution of their deaminase activity. Substitution of IMP for AMP causes a decrease of Ca2+ efflux from the vesicles. The data obtained are in good agreement with the assumption that the ammonium formation from AMP can favour the release of Ca2+ from some vesicles of SR.
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PMID:[Efflux of Ca2+ from fragmented sarcoplasmic reticulum during AMP deamination]. 50 58

The method of measuring enzyme deactivation by monitoring necessary addition of fresh enzyme to keep a constant degree of conversion in a CSTR at constant [E] x tau, the product of concentration of active enzyme [E] and residence time tau, was successfully applied to acylase I from porcine kidney and Aspergillus oryzae fungus. Fungal enzyme was found to be more stable than kidney enzyme. Activation by both Co2+ and Zn2+ ions also yielded increased operational enzyme stability: Co2+ and Zn2+ are better stabilizers than activators. Mg2+ and Ca2+ are found to be neither activators nor stabilizers. Fungal acylase partially deactivated by exposition to a metal-free medium in the CSTR was reactivated by addition of Zn2+, demonstrating that loss of Zn2+ from the enzyme molecule is mainly responsible for deactivation in a continuous reactor.
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PMID:Operational stability of enzymes. Acylase-catalyzed resolution of N-acetyl amino acids to enantiomerically pure L-amino acids. 147 69

L-alpha-aminocaprolactam hydrolase possessing the L lysine amidase activity was isolated from Klebsiella aerogenes and purified. The procedure of enzymes purification included cell destruction on USDN-I, fractionation by ammonium sulfate, gel chromatography on G-200. The preparation of the purified enzyme possessed specific activity of 50 mumol of lysin per 1 mg of protein per hour. Km was 2.6 mM in case of phosphate buffer (ph 7.2) for I-alpha-aminocaprolactam. Besides L-alpha-aminocaprolactam the enzyme hydrolyses lysine amide, leucine amide tryptophanamide. Magnesium ions are necessary for manifestation of catalytic activity of the enzyme.
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PMID:[Isolation and various properties of alpha-aminocaprolactam hydrolase from Klebsiella aerogenes]. 151 39

Purification to homogeneity of the N-acetylmuramoyl-L-alanine amidase (mucopeptide amidohydrolase, EC 3.5.1.28) from human serum has been achieved with a high yield. By molecular sieving chromatography, a molecular weight of 120,000-130,000 has been found for the native enzyme. Polyacrylamide gel electrophoresis under native conditions gave a unique band of Mr = 125,000. The same technique performed under denaturing conditions revealed that the protein is a dimer composed of one subunit of Mr = 57,000 and another of Mr = 70,000. In isoelectrofocalization assays, the amidase behaved as an acidic protein. Ethylenediaminetetraacetate inhibited the enzyme activity; the Mg2+ requirement was confirmed. The simultaneous presence of sulfhydryl groups and disulfide bonds in the protein was evidenced by the inhibitions produced by different thiol-blocking reagents and by several thiol-bearing substances. Direct measurements established the presence of two accessible thiol groups and the occurrence of nine disulfide bonds per protein molecule. Studies of substrate hydrolyzing capacities showed a marked preference for the muramoyl tripeptide derived from the Escherichia coli or Bacillus cereus mureins, the disaccharide tetrapeptide and the bis disaccharide tetra-tetrapeptide from E. coli were also good substrates. Activities on small muropeptides of other composition are also reported. Whole (insoluble) peptidoglycans representing the main bacterial chemotypes were submitted to the enzyme action; although with weak specific activities, the human amidase was nevertheless able to release soluble peptides from some of them. A bacteriolytic capacity on some microorganisms cannot be excluded. Results are discussed and the human enzyme is compared to presently known microbial muramoyl amidases.
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PMID:Purification and characterization of N-acetylmuramoyl-L-alanine amidase from human serum. 197 48

Depending on its concentration, phosphatidylglycerol, one of the three main Escherichia coli phospholipid species, is able to activate or inactivate the E. coli murein amidase (N-acetylmuramoyl-L-alanine amidase, EC 3.5.1.28) (Vanderwinkel, E. and De Vlieghere, M. (1985) Biochim. Biophys. Acta 838, 54-59). The mechanisms underlying the modulation of this enzyme activity were studied by analyzing the effects of cations, polycationic molecules, various surfactants and amphiphilic water-soluble compounds. K+, Mg2+ and polyamines were all able to prevent completely the enzyme inactivation produced by millimolar order concentration of phosphatidylglycerol. The efficiencies of the ionic species tested were in the order K+ less than Mg2+ = putrescine less than spermidine less than spermine. The kinetics of the counteraction processes were all sigmoidal. By contrast, the activation of the murein amidase produced by phosphatidylglycerol in micromolar concentration appeared to be insensitive to the ionic strength of the medium. Surfactants and amphiphilic molecules differing in their polar head and hydrophobic tail were found to activate the enzyme at various degrees for concentrations below their critical micellar concentration. The non-ionic surfactants were the most potent activators and remarkably mimicked the phosphatidylglycerol activation. The enzyme activation process appeared to require only a hydrophobic solvation shell around the protein. All kinetic data supported our previous interpretation of the phosphatidylglycerol-enzyme interactions in terms of multisite non-allosteric theory.
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PMID:Nature of the interactions involved in the lipid-protein complexes of the Escherichia coli N-acetylmuramoyl-L-alanine amidase. 288 30

The enzyme N-acetylmuramyl-L-alanine amidase (mucopeptide amidohydrolase, EC 3.5.1.28) has been detected in human, mouse, rabbit, bovine and sheep sera. A method for detection of amidase activity using [14C]peptidoglycan monomer as the substrate has been developed. Partial purification of human and mouse amidase was achieved by gel chromatography on Bio-Gel A-1.5 m, DEAE-Sephadex A-50 and Sephadex G-100. Both amidase preparations exhibited maximal activity at pH 9.0 in Tris-HCl buffer and required Mg2+ for maximal activity. Following digestion of peptidoglycan monomer, GlcNAc-MurNAc-L-Ala-D-isoglutaminyl-meso-diaminopimelyl-D-Ala-D-Ala, the disaccharide GlcNAc-MurNAc and the corresponding pentapeptide L-Ala-D-isoglutaminyl-meso-diaminopimelyl-D-Ala-D-Ala were formed and subsequently isolated and chemically characterized. The enzyme therefore acts as an N-acetylmuramyl-L-alanine amidase by cleaving the bond between N-acetylmuramic acid and L-alanine. The glycan linked, peptide-not-cross-linked peptidoglycan dimer was also shown to be a substrate for human and mouse amidase.
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PMID:Partial purification and characterization of N-acetylmuramyl-L-alanine amidase from human and mouse serum. 612 7

The role of phosphatidylinositol-specific phospholipase C (PIase C) in a) the enigmatic phosphatidylinositol (PI) turnover and b) in our understanding of membrane enzyme-PI interactions is the subject matter of this article. PIase C is present in both procaryotes and eukaryotes. This enzyme is considered to be involved in the cells PI breakdown which occurs in response to several external stimuli. Recent information on the physical properties, Ca2+ requirement, cellular localization and modulation of the activity of PIase C of mammalian systems can help to evaluate the PI turnover from a new angle. Existing evidence suggests that Ca2+-dependent PI breakdown is probably mediated through the cytosolic and particulate PIase C while a Ca2+ independent pathway is catalyzed by a lysosomal enzyme. Apparently PI turnover may be operating through more than one mechanism. The association of this phenomenon with a membrane receptor event linked with "Ca2+ gating" may have to be reconsidered. Modulation of the PIase C activity by unsaturated amphiphiles or the presence of this enzyme in different physico-chemical forms could be a potential regulatory feature. Hydrolysis of membrane PI of a number of cells and tissues by the bacterial PIase C has been shown to cause substantial release of acetylcholinesterase, alkaline phosphatase and 5'-nucleotidase in free, soluble form. Other membrane enzymes, e.g., alkaline phosphodiesterase I, L-leucyl-beta naphthyl amidase and Ca2+ or Mg2+ ATPase are not affected. These results indicate a specific interaction between PI and certain enzymes in membranes. The chemical nature of this linkage, whether it is covalent or non-covalent, has also been explored and has provided intriguing insight into this phenomenon. New findings also indicate that hydrolysis of PI by PIase C also can cause modifications in membrane-enzyme activities, e.g., adenylate cyclase.
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PMID:Minireview. Phosphatidylinositol specific phospholipases C. 708 67

The 2'5-diamino-6-ribitylamino-4(3H)-pyrimidinone 5'-phosphate deaminase was partially purified from cell extracts of Candida guilliermondii ATCC 9058. The enzyme requires Mg2+ for activity. Maximal activity was observed at pH 7,3. The enzyme converts its substrate, 2,5-diamino-6-ribitylamino-4(3H)-pyrimidinone 5'-phosphate, to 2,5-diamino-6-ribitylamino-2,4(1H,3H)-pyrimidinedione 5'-phosphate. This labile compound was treated with diacetyl and the resulting 6,7-dimethyl-8-ribityllumazine 5'-phosphate was identified by comparison with a synthetic sample.
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PMID:Biosynthesis of riboflavin. Characterization of the product of the deaminase. 731 43


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