Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.4.21.69 (APC)
 16,337 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Using affinity chromatography on a column of factor X-Cellulofine, we have isolated a novel blood coagulation factor X-binding protein with anticoagulant activity from the venom of Trimeresurus flavoviridis (Habu snake). This anticoagulant protein was also purified by chromatography on Sephadex G-75 and S-Sepharose Fast Flow. The yield of the purified protein was approximately 16 mg from 400 mg of crude venom. The purified protein gave a single band on both analytical alkaline disc-gel electrophoresis and SDS-PAGE. This protein had a relative molecular weight (Mr) after SDS-PAGE of 27,000 before reduction of disulfide bonds and 14,000 after reduction of disulfide bonds. The protein prolonged the clotting time induced by kaolin or factor Xa. In the presence of Ca2+, it formed a complex with factor X, the molar ratio being 1 to 1. Similar complex formation was observed with factor Xa and factor IX/factor IXa, but not with other vitamin K-dependent coagulation factors, i.e., prothrombin, factor VII, protein C, protein S, and protein Z. The interaction of this anticoagulant protein with factor IX/factor X was dependent on gamma-carboxyglutamic acid (Gla) domains, since Gla-domainless derivatives of factor X and factor IXa beta' did not interact with this anticoagulant protein.
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PMID:A novel blood coagulation factor IX/factor X-binding protein with anticoagulant activity from the venom of Trimeresurus flavoviridis (Habu snake): isolation and characterization. 261 88

The previously unassigned gene coding for the anti-coagulatory protein C has been mapped on chromosome 2 using a cDNA probe and genomic blots from a human-hamster somatic cell hybrid panel. The assignments of the genes coding for the coagulation factor X to chromosome 13, and for alpha 1-acid glycoprotein to chromosome 9 have been confirmed using a similar direct approach.
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PMID:Mapping through somatic cell hybrids and cDNA probes of protein C to chromosome 2, factor X to chromosome 13, and alpha 1-acid glycoprotein to chromosome 9. 346 31

The complete amino acid sequence of the light chain of human blood coagulation factor X has been determined by automated Edman degradation of peptides isolated from chemical and enzymatic digests of the carboxymethylated light chain. The protein consists of 139 amino acid residues, which include 11 residues of gamma-carboxyglutamic acid. The first 100 residues of the human factor X light chain exhibit approximately 80% homology when compared to the amino-terminal sequence of bovine factor X light chain. This homology decreases to approximately 50% in the remaining 39 residues of the carboxyl-terminal region of the protein. Proton nuclear magnetic resonance spectroscopy and mass spectrometry analyses of isolated residue 63 identified this residue as L-erythro-beta-hydroxyaspartic acid, a hitherto unrecognized amino acid in proteins. Evidence is also presented for the presence of this residue in the corresponding regions of the light chains of bovine factor X and bovine protein C. The biological function of beta-hydroxyaspartic acid in these proteins is unknown.
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PMID:Complete amino acid sequence of the light chain of human blood coagulation factor X: evidence for identification of residue 63 as beta-hydroxyaspartic acid. 687 Nov 67

The presence of gene lesions in coagulation factor X (FX, Stuart factor) was investigated in asymptomatic subjects with FX deficiency characterized by the presence of dysfunctional molecules in plasma, as demonstrated by the discrepancy between clotting activity and antigen level. A missense mutation (Ser334Pro) in the catalytic domain was found in three unrelated families in both the homozygous and the heterozygous conditions, and also in the compound heterozygous form with the substitution of Lys for 102 Glu. None of the mutations was detected in 40 unrelated subjects from the same geographic area. The Ser334Pro mutation affects a serine protease region characterized by extensive variation in the coagulation factors but conserved in mammalian factor X molecules. The Glu102Lys mutation affects a residue of the second EGF-like module also conserved in protein C. Both mutated residues are surface-exposed and found in protein regions suggested to be involved in macromolecular interactions which are impaired in the dysfunctional molecules.
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PMID:Molecular bases of CRM+ factor X deficiency: a frequent mutation (Ser334Pro) in the catalytic domain and a substitution (Glu102Lys) in the second EGF-like domain. 766 71

A flock of Rambouillet sheep experienced unexpected lamb mortality associated with excessive bleeding at the time of parturition. Most lambs died of blood loss through the umbilicus or into subcutaneous tissues. Subsequently, nine ewes which had previously delivered lambs that bled to death were bred to the suspected sire of the previous bleeding lambs. Fifteen lambs were born alive the following Spring, and three males and one female bled clinically. These lambs had markedly decreased factor IX (< 16%) and factor X (< 4%) activities, with variably decreased factor II (11-36%) and factor VII (20-37%) activities. Protein C chromogenic activity was also markedly decreased (< 1%) in these lambs. The results from crossed immunoelectrophoresis and 'protein-induced-in-vitamin-K-absence' determination of the plasma of affected lambs, with antiserum directed against coagulation factor X, protein C or proteins S, suggested that these proteins were not carboxylated normally. Examination of liver from one lamb in the first batch and the four subsequent lambs did not reveal a known vitamin K antagonist. The breeding data suggested that the coagulopathy in these sheep was inherited as an autosomal recessive trait. The genetic or molecular defect that exists in these lambs is unknown, but possibilities include abnormal gamma-glutamyl carboxylase activity or abnormal metabolism of vitamin K.
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PMID:Hereditary deficiency of vitamin-K-dependent coagulation factors in Rambouillet sheep. 1019 55

The structure and function of snake venom proteases are briefly reviewed by putting the focus on their effects on hemostasis and thrombosis and comparing with their mammalian counterparts. Up to date, more than 150 different proteases have been isolated and about one third of them structurally characterized. Those proteases are classified into serine proteases and metalloproteinases. A number of the serine proteases show fibrin(ogen)olytic (thrombin-like) activities, which are not susceptible to hirudin or heparin and perhaps to most endogenous serine protease inhibitors, and form abnormal fibrin clots. Some of them have kininogenase (kallikrein-like) activity releasing hypotensive bradykinin. A few venom serine proteases specifically activate coagulation factor V, protein C, plasminogen or platelets. The venom metalloproteinases, belonging to the metzincin family, generally show fibrin(ogen)olytic and extracellular matrix-degrading (hemorrhagic) activities. A few venom metalloproteinases show a unique substrate specificity toward coagulation factor X, platelet membrane receptors or von Willebrand factor. A number of the metalloproteinases have chimeric structures composed of several domains such as proteinase, disintegrin-like, Cys-rich and lectin-like domains. The disintegrin-like domain seems to facilitate the action of those metalloproteinases by interacting with platelet receptors. A more detailed analysis of snake venom proteases should find their usefulness for the medical and pharmacological applications in the field of thrombosis and hemostasis.
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PMID:Snake venom proteases affecting hemostasis and thrombosis. 1070 55

In the present study, a new functional test for the detection of increased resistance of coagulation factor V to degradation by activated protein C (factor V Leiden mutation) was evaluated. The STA-STACLOT APC-R Test (Diagnostica Stago, Asnieres, France) is based on the specific activation of factor X by Crotalus viridis helleri snake venom. The results are given as clotting time in seconds of the patient's plasma in the presence of venom and activated protein C. The intra-assay coefficient of variation was 2.17% (n=20) for samples within the normal range, and 1.70% and 1.42% (n=20) for the plasma of a heterozygous or a homozygous carrier of the factor V Leiden mutation, respectively. The inter-assay coefficient of variation (n=10) was 7.75% for the plasma of a healthy donor, 5.05% for the plasma of a heterozygous carrier and 3.38% for the plasma of a homozygous individual. The normal range (5th-95th percentile) of 136.4 s-174.7 s was derived from the clotting time of the plasma of 38 healthy controls. Values below 136 s were found in every sample from patients carrying the factor V Leiden mutation (n=52), whereas no patient with protein C (n=11) or protein S deficiency (n=10) had reduced clotting times. Homozygous carriers of the factor V Leiden mutation had clotting times shorter than 66.0 s and heterozygous carriers had clotting times longer than 80.0 s. Thus, based upon the individual clotting time, patients homozygous for factor V Leiden mutation could easily be distinguished from normals or heterozygous individuals. The influence of coagulation factor X, V, or II deficiency on the STACLOT APC-R Test was evaluated and revealed prolonged clotting times at factor V activities below 50%. In the presence of lupus anticoagulant the specificity of the STA-STACLOT APC-R Test was clearly decreased. In the present study, we clearly show that the STA-STACLOT APC-R Test is able to discriminate carriers of the factor V Leiden mutation from healthy controls or patients with protein C or protein S deficiency.
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PMID:Evaluation of a highly specific functional test for the detection of factor V Leiden. 1119 68

We isolated a novel protease that converts plasminogen to angiostatin-like fragments (BL-angiostatins) from a culture of Bacillus megaterium A9542 through a single-step chromatography on CM-cellulose. The protease, designated bacillolysin MA (BL-MA), belongs to a family of neutral metalloproteinases based on the nucleotide sequence of its gene. At an enzyme:substrate ratio of 1:540, BL-MA cleaved human plasminogen mainly at Ser441-Val442 to form BL-angiostatin and miniplasminogen with a K(m) of 3.0 +/- 0.8 microM and a k(cat) of 0.70 +/- 0.09 s(-1). The resulting BL-angiostatins inhibited the proliferation, migration, and tube formation of vascular endothelial cells at concentrations of 1-10 microg/ml. Although BL-MA failed to activate plasminogen, it increased urokinase-catalyzed activation of plasminogen caused by production of miniplasminogen, which is highly susceptible to activation. In addition, BL-MA was active in converting prourokinase, prothrombin, coagulation factor X, and protein C to their active forms. BL-MA enhanced both the clotting of human plasma and clot dissolution in the presence of prourokinase. Thus, BL-MA affects blood coagulation and fibrinolysis systems and can be used to produce angiostatin-like plasminogen fragments and active serine proteases of human plasma.
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PMID:Bacillolysin MA, a novel bacterial metalloproteinase that produces angiostatin-like fragments from plasminogen and activates protease zymogens in the coagulation and fibrinolysis systems. 1567 46

Activated protein C (APC) down-regulates thrombin formation through proteolytic inactivation of factor Va (FVa) by cleavage at Arg(506) and Arg(306) and of factor VIIIa (FVIIIa) by cleavage at Arg(336) and Arg(562). To study substrate recognition by APC, active site-mutated APC (APC(S360A)) was used, which lacks proteolytic activity but exhibits anticoagulant activity. Experiments in model systems and in plasma show that APC(S360A), and not its zymogen protein C(S360A), expresses anticoagulant activities by competing with activated coagulation factors X and IX for binding to FVa and FVIIIa, respectively. APC(S360A) bound to FVa with a K(D) of 0.11 +/- 0.05 nm and competed with active site-labeled Oregon Green activated coagulation factor X for binding to FVa. The binding of APC(S360A) to FVa was not affected by protein S but was inhibited by prothrombin. APC(S360A) binding to FVa was critically dependent upon the presence of Arg(506) and not Arg(306) and additionally required an active site accessible to substrates. Inhibition of FVIIIa activity by APC(S360A) was >100-fold less efficient than inhibition of FVa. Our results show that despite exosite interactions near the Arg(506) cleavage site, binding of APC(S360A) to FVa is almost completely dependent on Arg(506) interacting with APC(S360A) to form a nonproductive Michaelis complex. Because docking of APC to FVa and FVIIIa constitutes the first step in the inactivation of the cofactors, we hypothesize that the observed anticoagulant activity may be important for in vivo regulation of thrombin formation.
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PMID:Inhibition of thrombin formation by active site mutated (S360A) activated protein C. 2048 50

The aim of this study was to establish the reference values of hemostatic/fibrinolytic markers and investigate their relationship with physical constitution and cardiovascular risk factors in a normal schoolchildren population. This study comprised 148 healthy Japanese children aged 9-10 years (males 73; females 75). We performed laboratory tests including blood levels of leptin, high-sensitive C-reactive protein (hs-CRP), hemostatic and fibrinolytic markers [plasminogen activator inhibitor 1 (PAI-1), coagulation factor VII (FVII), coagulation factor X (FX), fibrinogen (Fbg), protein C, protein S], as well as common biochemical markers in the morning after an overnight fast. We investigated the mean, 10th, 50th and 90th percentile values of these markers. All parameters were compared between two groups, that is those with body mass index (BMI) 90th percentile or higher and BMI less than 90th percentile, and between subgroups based on the number of cardiovascular risk factors. Multiple-linear regression was used to assess associations between these hematological parameters and the components related to metabolic syndrome (MetS). Alanine aminotransferase (ALT), uric acid, leptin, hs-CRP, and all hemostatic/fibrinolytic markers (PAI-1, FVII, FX, Fbg, protein C, protein S) tested were significantly higher in the group with BMI 90th percentile or higher, and increased with accumulation of cardiovascular risk factors. Multiple-linear regression analysis showed that these values were associated with one or more components related to MetS. Reference values of hemostatic/fibrinolytic markers in Japanese schoolchildren were obtained. Many hemostatic/fibrinolytic markers showed significant association with BMI and accumulation of cardiovascular risk factors in normal Japanese schoolchildren.
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PMID:Significant associations between hemostatic/fibrinolytic systems and accumulation of cardiovascular risk factors in Japanese elementary schoolchildren. 2682 94


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