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Enzyme
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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. 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
Asymptomatic identical twins were found to show the prolonged activated partial
thromboplastin
time, which was corrected by addition of normal, Hageman factor deficient or Fletcher trait plasma but not corrected by Fitzgerald or Williams plasma. The prolonged activated partial
thromboplastin
time was also corrected by addition of highly purified bovine high molecular weight kininogen but not by low molecular weight kininogen. When total kininogen was measured as the amount of bradykinin released by trypsin on acid treated plasma, only trace amount was detected in Fujiwara and Williams plasmas, although Fitzgerald plasma showed approximately 50% of the total kininogen of normal plasma level. Acetone-kaolin activated
amidase
activity of plasma kallikrein was not generated by Fujiwara plasma. Substitution with normal plasma in various ratios showed plasma kallikrein activity proportionally to the normal plasma contents. Extrapolation with the values at 120 min after activation gave the prekallikrein content of Fujiwara plasma as 30% of the normal value.
...
PMID:Fujiwara trait: the first case of kininogen deficiency in Japan. 51 63
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
An anticoagulant isolated from salivary gland extracts of the ixodid tick Rhipicephalus appendiculatus was purified by gel filtration on Sephadex G-100, ion exchange on DEAE-cellulose, aprotinin-Sepharose, and by high-pressure-liquid size-exclusion chromatography. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed that the anticoagulant activity was associated with a protein of an apparent Mr of 65 kDa. The purified molecule had a pI in the range of 8.0-8.5 on chromatofocusing and was stable over a wide pH range, but was heat labile and susceptible to inactivation by trypsin and reductive alkylation. The anticoagulant did not inhibit thrombin-initiated fibrin formation and had no detectable fibrino(geno)lytic or phospholipase-like activities. Although it inhibited
factor Xa
-induced clotting of bovine plasma, it did not affect the
amidase
activity of
factor Xa
toward a synthetic substrate, suggesting that the anticoagulant acts at a site distinct from the active site of
factor Xa
or on other components of the
prothrombinase
complex.
...
PMID:Purification and characterization of an anticoagulant from the salivary glands of the ixodid tick Rhipicephalus appendiculatus. 202 16
The effect of divalent and monovalent cations on the hydrolysis of BzIleGlu(OR)GlyArgpNA(S-2222) was compared to the rate of inactivation of
factor Xa
by dansyl-GluGlyArg-chloromethylketone(DERG-CK). At substrate concentrations below Km, an approximate four-fold increase in
amidase
activity was observed in the presence of manganese ions while a three-fold increase was observed with calcium ions. The presence of magnesium ions resulted in a two-fold increase in
amidase
activity. Similar increases in the rate of inactivation of
factor Xa
by DERG-CK were observed. Na+ ions had a marked enhancing effect of both
factor Xa
amidase
activity and inactivation by DERG-CK. Kinetic parameters for the hydrolysis of S-2222 by
factor Xa
were obtained in the presence and absence of Ca++ and Na+. Vmax values increased in the presence of either Ca++ or Na+. Km values increased in the presence of Ca++ while there was a modest decrease in Km in the presence of Na+. It is suggested that the enhanced activity of
factor Xa
is a reflection of changes in the reactivity of active site residues.
...
PMID:Influence of divalent and monovalent cations on some active site properties of human factor Xa. 316 82
A low molecular weight protein protease inhibitor was purified from Japanese horseshoe crab (Tachypleus tridentatus) hemocytes. It consisted of a single polypeptide with a total of 61 amino acid residues. This protease inhibitor inhibited stoichiometrically the
amidase
activity of trypsin (Ki = 4.60 X 10(-10) M), and also had inhibitory effects on alpha-chymotrypsin (Ki = 5.54 X 10(-9) M), elastase (Ki = 7.20 X 10(-8) M), plasmin, and plasma kallikrein. However, it had no effect on T. tridentatus clotting enzyme and factor C, mammalian blood coagulation factors (activated protein C,
factor Xa
and alpha-thrombin), papain, and thermolysin. The complete amino acid sequence of this inhibitor was determined and its sequence was compared with those of bovine pancreatic trypsin inhibitor (BPTI) and other Kunitz-type inhibitors. It was found that the amino acid sequence of this inhibitor has a high homology of 47 and 43% with those of sea anemone inhibitor 5-II and BPTI, respectively. Thus, this protease inhibitor appeared to be one of the typical Kunitz-type protease inhibitors.
...
PMID:Purification and amino acid sequence of Kunitz-type protease inhibitor found in the hemocytes of horseshoe crab (Tachypleus tridentatus). 330 64
Poly-L-lysine has been demonstrated to partially replace biological cofactors in the activation of prothrombin by
factor Xa
. The present study was initiated to determine if poly-L-lysine has an effect on the enzymatic activity of
factor Xa
in the absence of prothrombin. At low ionic strength (50 mM Tris-Cl, pH 8.0, ambient temperature), poly-L-lysine inhibits
amidase
activity (S-2222) of bovine
factor Xa
with high affinity (Ki = 7 nM). The inhibition was readily reversed by 100 mM NaCl. The inhibition was also markedly reduced by the addition of 1.0 mM CaCl2 but not by MnCl2 or MgCl2. All three metal ions enhance
amidase
activity in the absence of poly-L-lysine. Poly-L-lysine also inhibits the
amidase
activity of
factor Xa
from which the gamma-carboxyglutamic acid domain has been removed by limited proteolysis with chymotrypsin (
factor Xa
-GD) but with somewhat lower avidity (Ki = 35 nM). As with native
factor Xa
, calcium ions reduce the observed inhibition while either manganese or magnesium ions are much less effective. The
amidase
activity of
factor Xa
-GD is enhanced with any one of the three divalent cations. These results provide additional support for the existence of a functionally significant binding site for calcium ions outside of the gamma-carboxyglutamic domain of
factor Xa
.
...
PMID:Interaction of polylysine with bovine factor Xa: effect of divalent cations. 348 86
In separate experiments, antibodies to plasminogen, factor X and protein C were applied to microtitre trays as commonly used in enzyme-linked immunoassays. After incubation with dilute normal human plasma as a source of the corresponding proenzyme antigen, the wells were exposed to dilutions of various snake venoms. After thorough washing, the microtitre tray wells were tested overnight with chromogenic tripeptide substrates known to be relatively specific for the activated forms of the above factors, i.e., plasmin,
factor Xa
and activated protein C. The immunochromometric assay described detected two new activators of protein C in Agkistrodon piscivorus and Agkistrodon contortrix venoms and a new factor X activator in Agkistrodon rhodostoma venom. Gel filtration of the latter venom indicated that the factor X activator eluted with high molecular weight, was clearly distinct from the peak fibrinogen clotting activity (Ancrod) and appeared to have no procoagulant activity. Although several Bothrops venoms appeared to contain plasminogen activator by this technique, the observed strong chromogenic activity was observed in microtitre wells independently of plasminogen and represented nonspecific
amidase
activity.
...
PMID:Detection of specific proenzyme activators in snake venoms by a new immunoabsorbant-chromogenic substrate method. 384 Oct 12
A study was made of the interaction between prothrombin and enzymes: blood plasma kallikrein and factors alpha-XIIa and beta-XIIa immobilized on enzacryl-AH. Kallikrein-induced prothrombin proteolysis was accompanied by a decrease in prothrombin activity, appearance of BAME-esterase and poor clotting activity. As a result of fractionation of products on the column with DEAE-Sephadex A-50, some fractions that have thrombin
amidase
activity (splitting of the substrate S-2238) and high antithrombin activity were obtained. Antithrombin activity manifested in the inhibition of fibrinmonomer aggregation during fibrin formation. During incubation with prothrombin, factors alpha-XIIa and beta-XIIa also stimulated the appearance of BAME-esterase activity. None of the immobilized enzymes
activated factor X
.
...
PMID:[Prothrombin--substrate for blood plasma kallikrein and factor XIIa]. 660 74
Vipera russellii venom was separated into thirteen fractions by means of DEAE-Sephadex A-50 column chromatography. Fraction III possessed anticoagulant and phospholipase A activities and Fraction XI possessed procoagulant and caseinolytic activities, both were further purified by gel filtration on Sephacryl S-200 column. Purified procoagulant (Component II) was a two-chain protein with molecular weight of 86 000 consisting of A-chain (Mr 66 000) and B-chain (Mr 20 000). It was a glycoprotein containing 7.8% neutral sugar and 715 amino-acid residues. The procoagulant activity was 10-times that of the crude venom. It was an acidic proteinase with isoelectric point of pH 4.2. Upon heat treatment at 60 degrees C, Component II was stable at pH 5.5 and 7.2 for 3 h, but was destroyed completely after 30 min at pH 8.9. It was devoid of esterase or
amidase
activity. Purified anticoagulant (Component I) was a single peptide chain with molecular weight of 16 000. It was carbohydrate free and contained 136 amino-acid residues. It was a basic protein with an isoelectric point of larger than pH 10. It was a potent phospholipase A with an enzymatic activity of 510 +/- 30 mumol/min per mg using phosphatidylcholine as substrate, and 1 microgram/ml was sufficient to cause 100% hemolysis by the indirect hemolytic method. Upon heat treatment at 90 degrees C, Component I was heat stable at pH 5.5 for more than 3 h, but was destroyed completely after 2 h at pH 7.2 and 8.9. The anticoagulant activity of Component I could be neutralized by platelet factor 3, tissue
thromboplastin
and cephalin.
...
PMID:Purification and properties of the main coagulant and anticoagulant principles of Vipera russellii snake venom. 672 70
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