Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.5.1.4 (deaminase)
5,113 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

1. Preparations of purified pig kidney aminoacylase (N-Acylamino-acid amidohydrolase, EC 3.5.1.14) were obtained by Sephadex and DEAE-cellulose chromatography in homogeneous form as judged by polyacrylamide gel electrophoresis and immunoelectrophoresis. 2. The apparent molecular weight of the enzyme, determined by gel filtration, was about 86 000. After treatment with mercaptoethanol, performic acid or sodium dodecyl sulphate a band with an apparent molecular weight of approximately 43 000 was observed in polyacrylamide gels containing sodium dodecyl sulphate. Thus pig kidney aminoacylase seems to be composed of two subunits. 3. The amino acid composition of the enzyme was determined. Aminoacylase contains 772 amino acids, which corresponds to a molecular weight of 85 500. 12 tryptophan and 12 half-cystine residues were found. 4. Each subunit of the enzyme contains two -SH groups of different reactivity and two disulfide bonds one of which is easily cleaved by -SH compounds, the second only by performic acid oxidation. 5. Chemical modification of two -SH groups abolishes the catalytic activity of aminoacylase. Cleavage of two disulfide bonds also inactivates the enzyme. It is suggested that the enzyme has two active sites each containing an essential -SH group and disulfide bond. One active site is assumed to be part of each subunit.
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PMID:Chemical investigations on pig kidney aminoacylase. 0 49

Microsomal AMP-deaminase was solubilized by 0.5 M KCl after treatment of microsomal membranes with 0.12 M KCl. Using disc-electrophoresis in polyacrylamide gel in the presence of sodium dodecyl sulfate one major protein component (mol. weight about 90 000) and three minor ones with molecular weights of 110 000, 80 000, and 60 000 were found in the soluble fraction. In addition to proteins, the fraction was found in the soluble fraction. In addition to proteins, the fraction was found to contain a small amount of phospholipids. The deaminase found in the solution may be reconstructed into the membranes at a decrease in KCl concentration, part of enzyme being bound in the inactive form under excess of the soluble fraction. Deaminase binding to the membranes is unaffected by the changes within the pH range of 6.2--7.8 and temperature range of 4--10 degrees C. It is assumed that AMP-deaminase is bound to other membrane components by electrostatic bonds.
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PMID:[Solubilization and reconstruction of microsomal AMP-deaminase from skeletal muscles]. 2 Jan 65

Formamidase from rat liver proved to be microheterogenous. After preparative isoelectric focusing in density gradient columns, two peaks of formamidase with identical substrate specificity were identified. By analytical focusing in thin layers of polyacrylamide or Sephadex G-75 SF, even five bands could be separated. Their isoelectric points were 4.75, 4.78, 4.82, 4.92 (main band) and 5.11, but their Michaelis constants did not differ significantly (54 to 62 mumol/l). An identical molecular weight of 34700 +/- 3200 for all bands was determined by disc electrophoresis. This value was confirmed by sedimentation analyses (so20,w = 3.00 S) and electrophoresis in the presence of sodium dodecyl-sulfate (Mr 34900 +/- 2300), which only gave a single band. The homogeneity was also confirmed by electrophoresis in the presence of 6M urea. Repeated disc electrophoresis of focusing under native conditions with single, isolated formamidases again resulted in different bands which were identified, not only by Coomassie Blue, but also by their hydrolytic cleavage of naphthyl acetate. Formamidase showed neither proteolytic nor asparagine-amidohydrolase activity and oligosaccharide conjugates were not detectable. Ampholytes, buffer ions, pH and peroxodisulfate did not affect the heterogeneity. "Initial burst" measurements with diethyl(4-nitrophenyl) phosphate yielded an equivalent weight of 36,300. Formylkynurenine reduced this inhibition very effectively. Thus, an extraordinary reactive serine residue appeared to be located in the catalytic site of formamidase. A participation of sulfhydrylgroups in the inactivating reaction of arsenite was excluded although two such groups were detected by 5,5'-dithiobis(2-nitrobenzoic acid). N-Bromosuccinimide reacted primarily with one of the nine tryptophan residues without loss of enzymatic activity, but a 18.6-fold excess of this reagent resulted in a complete loss of activity. The reaction rates of the most effective inhibitors and of the protective action of formylkynurenine were determined. Thus, formamidase must clearly be distinguished from typical serine esterases and proteases.
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PMID:[Formamidase--microheterogeneity, catalytic properties and inhibitors (author's transl)]. 8 81

The 16S and 8S forms of acetylcholinesterase (AchE), which are composed of an elongated tail structure in addition to the more globular catalytic subunits, were extracted and purified from membranes from Torpedo californica electric organs. Their subunit compositions and quaternary structures were compared with 11S lytic enzyme which is derived from collagenase or trypsin treatment of the membranes and devoid of the tail unit. Upon sodium dodecyl sulfate-polyacrylamide gel electrophoresis in the absence of reducing agent, appreciable populations of monomeric through tetrameric species are observed for the 11S form. Under the same conditions, the 16S form yields only monomer and dimer in addition to a higher molecular weight species. If complete reduction is effected, only the 80,000 molecular weight monomer is dominant for both the 11S and 16S forms. Cross-linking of the 11S form by dimethyl suberimidate followed by reduction yields monomer through tetramer in descending frequency, while the 16S form again shows a high molecular weight species. A comparison of the composition of the 11S and 16S forms reveals that the latter has an increased glycine content, and 1.1 and 0.3 mol % hydroxyproline and hydroxylysine, respectively. Collagenases that have been purified to homogencity and are devoid of amidase and caseinolytic activity, but active against native collagen, will convert 16S acetylcholinesterase to the 11S form. Thus, composition and substrate behavior of the 16S enzyme are indicative of the tail unit containing a collagen-like sequence. A membrane fraction enriched in acetylcholinesterase and components of basement membrane can be separated from the major portion of the membrane protein. The 16S but not the 11S form reassociates selectively with this membrane fraction. These findings reveal distinct similarities between the tail unit of acetylcholinesterase and basement membrane components and suggest a primary association of AchE with the basement membrane.
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PMID:Molecular forms of acetylcholinesterase from Torpedo californica: their relationship to synaptic membranes. 17 42

The molecular weights of purified calotropain-FI and FII were determined by sodium dodecyl sulphate-polyacrylamide gel electrophoresis and by filtration of Sephadex G-100. Activation of calotropain-FI and FII by different sulfhydryl activators was studied. The results obtained from inhibition studies by various enzyme-modifying reagents suggest the possible role of cysteine and histidine residues in the active site of both the enzymes. The free and total sulfhydryl contents of both the enzymes were determined by the use of 5-5'-dithio-bis-2-nitrobenzoic acid. Total amino acid compositions of both the enzymes were also determined. A comparative study of the esterase, amidase, milk-clotting and caseinolytic activities of calotropain-FI and FII are also presented.
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PMID:Studies on proteinases from Calotropis gigantea latex. II. Physico-chemichal properties of calotropain-FI and FII. 44 38

Protein C is a vitamin K-dependent protein, which exists in bovine plasma as a precursor of a serine protease. In this study, protein C was isolated to homogeneity from human plasma by barium citrate adsorption and elution, ammonium sulfate fractionation, DEAE-Sephadex chromatography, dextran sulfate agarose chromatography, and preparative polyacrylamide gel electrophoresis. Human protein C (M(r) = 62,000) contains 23% carbohydrate and is composed of a light chain (M(r) = 21,000) and a heavy chain (M(r) = 41,000) held together by a disulfide bond(s). The light chain has an amino-terminal sequence of Ala-Asn-Ser-Phe-Leu- and the heavy chain has an aminoterminal sequence of Asp-Pro-Glu-Asp-Gln. The residues that are identical to bovine protein C are underlined. Incubation of human protein C with human alpha-thrombin at an enzyme to substrate weight ratio of 1:50 resulted in the formation of activated protein C, an enzyme with serine amidase activity. In the activation reaction, the apparent molecular weight of the heavy chain decreased from 41,000 to 40,000 as determined by gel electrophoresis in the presence of sodium dodecyl sulfate. No apparent change in the molecular weight of the light chain was observed in the activation process. The heavy chain of human activated protein C also contains the active-site serine residue as evidenced by its ability to react with radiolabeled diisopropyl fluorophosphate. Human activated protein C markedly prolongs the kaolin-cephalin clotting time of human plasma, but not that of bovine plasma. The amidolytic and anticoagulant activities of human activated protein C were completely obviated by prior incubation of the enzyme with diisopropyl fluorophosphate. These results indicate that human protein C, like its bovine counterpart, exists in plasma as a zymogen and is converted to a serine protease by limited proteolysis with attendant anticoagulant activity.
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PMID:Human plasma protein C: isolation, characterization, and mechanism of activation by alpha-thrombin. 46 91

Threonine deaminase (L-theonine hydro-lyase (deaminating), E.C. 4.2.1.16) has been purified to homogeneity from extracts of Saccharomyces cerevisiae. When purified 1200-fold, the enzyme is homogeneous by the criterion of sodium dodecyl sulfate-polyacrylamide electrophoresis. The reduced and alkylated protein has a molecular weight of approximately 50,000 daltons, one-fourth the value determined previously for the intact enzyme. The purified enzyme exhibits homotropic effects with the substrate; these effects are descresed in the presence of DL-allothreonine, a competitive inhibitor. Half-maximal velocity is achieved at 34 mM L-threonine in the absence of other effectors. L-isoleucine both stimulates at low (0.01-0.05 mM) concentrations and inhibits at high (0.1-1.0 mM) concentrations. Valine activates the enzyme in the absence of isoleucine ; in the presence of isoleucine it reverses inhibition.
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PMID:Purification and properties of threonine deaminase from Saccharomyces cerevisiae. 78 58

Protease I, a periplasmic endopeptidase from Escherichia coli has been further purified by a modified procedure. While the purified protein consists of a single polypeptide chain of about 21000 daltons, its molecular weight in dilute salt solution was estimated to be near 43000, suggesting that the enzyme has a marked tendency to dimerize. It has only one disulphide bond and is very sensitive to urea. In agreement with previous evidence of a chymotrypsin-like specificity, hydrolytic assays of various p-nitrophenyl esters of N-substituted amino acids showed that phenylalanine and tyrosine derivatives are the best substrates for the enzyme. The Km(app) for N-benzoyloxycarbonyl-L-tyrosin-p-nitrophenyl ester at pH 7.5 In 100 mM sodium phosphate buffer at 25 degrees C was found to be 0.2 mM. In contrast to chymotrypsin, protease I is unable to hydrolyse N-acetyl-L-phenylalanine ethyl ester and its tyrosine analogue. Moreover, the enzyme appears devoid of amidase activity and exhibits a low activity upon polypeptides. At 37 degrees C, it cleaves the carboxymethylated B-chain of bovine insulin at four points: Phe25-Tyr26, Phe24-Phe25, Leu15-Tyr16 and Ser9-His10. From a detailed study of peptides bonds hydrolyzed, it was concluded that protease I has a stringent requirement for both residues forming the scissile bond, and appears to possess an extended hydrophobic binding site.
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PMID:Protease I from Escherichia coli. Some physicochemical properties and substrate specificity. 79 43

Further properties of cow liver deaminase are reported. Highly purified deaminase migrated as a single badn on starch and polycrylamide gels electrophoresis. Molecular weight determinations by means of gel filtration on calibrated columns of Sephadex G-100, Sepharose 4 B and B 10-Gel P-100, gave values of 40 000 +/- 4 000. Data obtained suggest that cow liver deaminase exists as a single polypeptide chain. Heating partially purified preparations of deminase resulted in an enhancement of activity. Added cosynthetase to these fractions increased the percentage of uroporphyrinogen III formed but also diminished total uroporphyrinogens synthesis. The action of several compounds added to the system was studied. Thiol reagents and divalent metals as Hg 2+ , Pb2+, (d2+ and Zn2+ inhibited deaminase, indicating the presence of thiol groups essential for activity, probably involved in the cyclization step. Certain concentrations of sodium, potassium and magnesium salts enhanced activity. Several chelators tested were without effect on the deminase. Some dicarboxylic acids and 2-methoxy-5-nitrotropone inhibited the enzyme.
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PMID:Studies on cow liver porphobilinogen deaminase. 105 1

Angiotensin II has been found to stimulate 5'-adenylic acid deaminase from rabbit skeletal muscle. Stimulation was discernible around 10(-9) M and peak stimulation of about threefold was seen at 10(-7) M, concentrations approximating those required for stimulation of vascular smooth muscle or adrenal glomerulosa cells. Higher concentrations produced less stimulation. Adenosine triphosphate stimulated to the same degree, but a concentration of 10(-5) M was required for maximum stimulation, while maximum stimulation with sodium or potassium required 0.5 M and 0.75 M, respectively. Although the physiologic significance of these observations has not been established, these data suggest an intracellular role for angiotensin II.
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PMID:Angiotensin II stimulation of 5'-adenylic acid deaminase. 125 Aug 47


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