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)

Deoxycytidine kinase, which phosphorylates deoxycytidine (CdR) and its analog, cytosine arabinoside (ara-C), has been purified 71-fold from human leukemic cells. Biochemical properties of the partially purified enzyme included a molecular weight of 68,000, Kms of 7.8 muM for CdR and 25.6 muM for ara-C, and optimal activity with ATP and GTP as phosphate donors. Ara-C phosphorylation was strongly inhibited by CdR (Ki = 0.17 muM) and dCTP (Ki = 7.3 muM) and was weakly inhibited by ara-CTP (Ki = 0.13 mM). Purification by calcium phosphate gel elution and DEAE chromatography effectively separated this enzyme from cytidine deaminase, which deaminates both CdR and ara-C, and from uridine-cytidine kinase, the enzyme which phosphorylates 5-azacytidine. CdR kinase activity was found to decrease and cytidine deaminase to increase with maturation of normal and leukemic granulocytes. Myeloblasts purified by Ficoll sedimentation revealed an average kinase activity of 15.4 U/mg protein in acute myelocytic leukemia and 12.3 U/mg protein in blastic crisis of chronic myelocytic leukemia (CML). The average ratio of CdR kinase to deaminase activity in crude cell extracts varied from 0.197 in AML and 0.089 in blastic crisis to 0.0004 in normal granulocytes, reflecting the changes which take place with cellular maturation. The absolute levels of kinase and deaminase and the ratio of these two enzymes varied considerably among patients with AML, indicating that quantitative differences may be found in the metabolism of CdR and its analogs in leukemic cells.
 ...
PMID:Deoxycytidine kinase: properties of the enzyme from human leukemic granulocytes. 5 55

We have previously demonstrated the existence of two types of endopeptidase in Escherichia coli. A purification procedure is described for one of these, designated protease II. It has been purified about 13,500-fold with a recovery of 24%. The isolated enzyme appears homogeneous by electrophoresis and gel filtration. Its molecular weight is estimated by three different methods to be about 58,000. Its optimal pH is around 8. Protease II activity is unaffected by chelating agents and sulfhydryl reagents. Amidase and proteolytic activities are stimulated by calcium ion, which decreases the enzyme stability. Like pancreatic trypsin, this endopeptidase catalyses the hydrolysis of alpha-amino-substituted lysine and arginine esters. It appears distinct from the previously isolated protease I, which is a chymotrypsin-like enzyme. The apparent Michaelis constant for hydrolysis of N-benzoyl-L-arginine ethyl ester is 4.7 X 10(-4) M. The esterase activity is inhibited by diisopryopylphosphorofluoridate (Ki(app) equals 2.7 X 10(-3) M) and tosyl lysine chloromethyl ketone (Ki(app) equals 1.8 X 10(-5) M), indicating that serine and histidine residues may be present in the active site. However, protease II is insensitive to phenylmethanesulfonyl fluoride and several natural trypsin inhibitors. Its amidase and esterase activities are competitively inhibited by free arginine and aromatic amidines. The proteolytic activity measured on axocasein is very low. In contrast to trypsin, protease II is without effect on native beta-galactosidase. It easily degrades aspartokinase I and III. Nevertheless both enzymes are resistant to proteolysis in the presence of their respective allosteric effectors. These results provide further evidence that such differences in protease susceptibility can be related to the conformational state of the substrate. The possible implication of structural changes in the mechanism of preferential proteolysis in vivo, is discussed.
 ...
PMID:Protease II from Escherichia coli. Purification and characterization. 24 Aug 39

1. Incubation of decarboxyfactor X with the factor X-activating enzyme from Russell's Viper venom revealed the generation of amidase activity towards Bz-Ile-Glu-Gly-Arg-pNA, but not of activity in blood coagulation. 2. The rate of activation of both factor X and decarboxyfactor X depends on the ability of the zymogens to bind Ca2+. The relationship between Ca2+ concentration and velocity of the activation reaction is sigmoid in the case of factor X, but hyperbolic with decarboxyfactor X. 3. Activated decarboxyfactor X was purified by powder column electrophoresis. 4. Identical changes of primary structure accompanied the activation of factor X and decarboxyfactor X. Identical molecular weight and common antigenic determinants were found in factor Xa and decarboxyfactor Xa. The amino acid composition was identical except for 12 glutamic acid residues in decarboxyfactor Xa and gamma-carboxyglutamic acid residues in factor Xa. 5. Unlike factor X, activated factor X has a very low electrophoretic mobility in the presence of Ca2+ at pH 8.6. This is probably due to self association of factor Xa under the influence of Ca2+. The electrophoretic mobility of activated decarboxyfactor X is only slightly decreased compared to decarboxyfactor X in the presence of Ca2+.
 ...
PMID:Activation of decarboxyfactor X by a protein from Russell's viper venom. Purification and partial characterization of activated decarboxyfactor X. 41 34

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.
 ...
PMID:[Efflux of Ca2+ from fragmented sarcoplasmic reticulum during AMP deamination]. 50 58

Total protein, alpha1-antitrypsin, alpha2-macroglobulin, amylase, methemalbumin, tryptic amidase activity, radioimmunoassayable elastase 2, and three lysosomal hydrolases were determined in the ascites fluid from patients with acute pancreatitis. In eight patients methemalbumin was detected in ascites and serum, supporting the diagnosis of hemorrhagic pancreatitis. Significant levels (4-45 microgram/ml) of tryptic amidase activity were detected in ascites samples from all patients. Evidence is presented which demonstrates that the tryptic amidase activity is due to alpha2-macroglobulin-bound trypsin. Pancreatic elastase 2, determined with a new sensitive and specific radioimmunoassay, ranged from 400 to 2100 ng/ml in serum and from 650 to 4460 ng/ml in ascites fluid. Substantial amounts of alpha2-macroglobulin-bound trypsin and elastase 2, entering the circulation from the peritoneal cavity, might be responsible for certain serious complications seen in acute pancreatitis. However, with the exception of serum calcium and methemalbumin and the ascites fluid methemalbumin and total protein, none of the biochemical parameters studied showed a distinct correlation with the patient's outcome.
 ...
PMID:Studies on the ascites fluid of acute pancreatitis in man. 62 83

The esterolytic and amidolytic properties of activated blood coagulation factor X (factor Xa) and the analogous decarboxy species were compared in order to find out if the gamma-carboxyglutamic acid residues influence the function of the active centre. It was found that the two proteins (1) showed similar kinetic parameters when titrated with p-nitrophenyl-p'-guanidinobenzoate hydrochloride (2) had a similar Km and kcat for various synthetic chromogenic tri- and tetrapeptides and (3) were inhibited in the same way by benzamidine. Further it was observed that (4) Ca2+ inactivates factor Xa, but has no influence on the amidase activity of decarbyxyfactor Xa (5) factor V prevents Ca2+-induced inactivation of factor Xa but does not influence the amidase activity of both factor Xa and decarboxyfactor Xa. We conclude that the interaction of the gamma-carboxyglutamic acid residues with Ca2+ in factor X has no measurable influence on the properties of the active site per se.
 ...
PMID:The effect of gamma-carboxyglutamate residues on the enzymatic properties of the activated blood clotting factor X. I. Activity towards synthetic substrates. 64 13

Two kinds of acidic arginine amidase activity were found in boar sperm. One enzyme was separated by a treatment consisting of lima bean trypsin inhibitor (LBTI) affinity adsorption and elution. The other enzyme was separated by aprotinin affinity adsorption and elution through the same solutions as those used for first enzyme; the two enzymes provisionally named boar sperm acidic arginine amidases 1 (BSAA-1) and 2 (BSAA-2), respectively. The amidolytic activity of BSAA-1 was increased by high concentrations of calcium chloride, while the activity of BSAA-2 was independent of calcium chloride. Their behavior with LBTI and aprotinin, and profiles of their substrate specificities, were also different. The affinity of LBTI to BSAA-1 was approximately 14 times higher than that to BSAA-2.
 ...
PMID:Detection and separation of two kinds of acidic arginine amidases from boar sperm using lima bean trypsin inhibitor and aprotinin affinity adsorptions. 137 93

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.
 ...
PMID:Operational stability of enzymes. Acylase-catalyzed resolution of N-acetyl amino acids to enantiomerically pure L-amino acids. 147 69

1. Two chymotrypsins, called chymotrypsin I and II, were purified from the pyloric caeca of rainbow trout, by (NH4)2SO4 fractionation, hydrophobic interaction chromatography (phenyl-Sepharose) and ion-exchange chromatography (DEAE-Sepharose). 2. The approximate molecular weights of chymotrypsin I and II were 28,200 (+/- 1200) and 28,800 (+/- 900), respectively, as determined by SDS-PAGE and their isoelectric points were about 5. 3. The pH optima of the enzymes were centered around nine, when assayed for succinyl-L-Ala-L-Ala-L-Pro-L-Phe-p-nitroanilide (Suc-AAPF-NA) as substrate and both enzymes were unstable at pH values below 5. 4. The amidase activity of both enzymes increased with temperature up to about 55 degrees C. Chymotrypsin I was found to be more heat stable than chymotrypsin II, an effect most likely explained by stronger calcium binding of the former. 5. The trout chymotrypsins were significantly more active than bovine alpha-chymotrypsin when assayed against Suc-AAPF-NA at 25 degrees C and casein at low temperatures (10-20 degrees C), indicating an adaptation of the activities of the trout chymotrypsins to the habitation temperatures of the fish.
 ...
PMID:Purification and characterization of two chymotrypsin-like proteases from the pyloric caeca of rainbow trout (Oncorhynchus mykiss). 149 72

An enzyme preparation with affinity to a lysine column was detected from a DEAE-cellulose-adsorbed preparation of human seminal plasma containing plasminogen and plasmin. Two kinds of trypsin-like acidic arginine amidase activity with different affinity to lima bean trypsin inhibitor (LBTI) and aprotinin affinity column were detected from the DEAE-cellulose-adsorbed preparation after treatment of the lysine column. Two kinds of trypsin-like basic arginine amidase activity were also separated by the above-mentioned affinity adsorptions from a CM-cellulose-adsorbed preparation of human seminal plasma. The effect of calcium chloride on these two enzymes was different from human acrosin.
 ...
PMID:Trypsin-like arginine amidases including plasminogen and plasmin in human seminal plasma by affinity adsorption and elution. 153 Mar 64


1 2 3 4 5 6 7 8 9 10 Next >>