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)

We have isolated overlapping phage genomic clones covering an area of 21 kilobases that encodes the human protein C gene. The gene is at least 11.2 kilobases long and is made up of nine exons and eight introns. Two regions homologous to epidermal growth factor and transforming growth factor are encoded by amino acids 46-91 and 92-136 and are precisely delimited by introns, as is a similar sequence in the genes for coagulation factor IX and tissue plasminogen activator. When homologous amino acids of factor IX and protein C are aligned, the positions of all eight introns correspond precisely, suggesting that these genes are the product of a relatively recent gene duplication. Nevertheless, the two genes are sufficiently distantly related that no nucleic acid homology remains in the intronic regions and that the size of the introns varies dramatically between the two genes. The similarity of the genes for factor IX and protein C suggests that they may be the most closely related members of the serine protease gene family involved in coagulation and fibrinolysis.
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PMID:Evolution and organization of the human protein C gene. 351 71

Human protein C is a vitamin K-dependent plasma protein that serves as a feedback down-regulator of the coagulation cascade by specifically degrading the protein cofactors VIIIa and Va. The protein C precursor consists of the following domains: leader peptide, "gla" region, two epidermal growth factor segments, and the activation peptide/serine protease. Comparison of amino acid sequences reveals that protein C and factor IX are homologous. A comparison of the genes for protein C and factor IX shows that all seven of the introns within the protein coding regions are in identical positions and correspond to protein structure-function domain boundries. However, the base compositions of the two genes (coding and noncoding regions) are remarkably different: approximately 60% guanine + cytosine (G + C) for protein C versus approximately 40% G + C for factor IX. One possible explanation for this phenomenon is that the factor IX gene (located on the X chromosome) has undergone extensive deoxycytosine methylation and subsequent spontaneous deamination mutagenesis, resulting in a net C to thymine (and G to adenine) transition. This would suggest that the protein C gene may represent a more primitive form of the gene duplication precursor.
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PMID:Structure and evolution of the human genes encoding protein C and coagulation factor IX. 357 41

Five type I protein C deficient male patients received 5 mg stanozolol b.i.d. during 4 weeks. After four weeks of treatment plasma protein C activity increased from 0.42 to 0.74 U/ml and protein C antigen from 0.49 to 0.75 U/ml. This approximately 1.6 fold increase in plasma protein C was accompanied by an increase in factor II antigen (1.5 fold), factor V activity (1.6 fold), factor X antigen (1.1 fold), antithrombin III antigen (1.3 fold) and heparin cofactor II antigen (1.5 fold), while the concentration of factor VII, factor VIII, and factor IX activity, and of protein S antigen remained unchanged. Prothrombin fragment F1+2, measured in two patients, increased 1.3 fold. In addition to its effect on procoagulant and anticoagulant factors stanozolol had profibrinolytic effects, reflected in an increase in tPA activity and in the concentration of plasminogen. These data indicate that in type I protein C deficient patients stanozolol increases the concentrations of both procoagulant and anticoagulant factors and favours fibrinolysis. The efficacy of stanozolol in preventing thrombotic disease in type I protein C deficient patients, however, remains to be established. During the four weeks of stanozolol treatment no thrombotic manifestations were observed in the protein C deficient patients.
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PMID:Treatment of hereditary protein C deficiency with stanozolol. 359 78

We isolated protein C from a barium citrate-adsorbed fresh plasma and human factor IX concentrate by immunoaffinity chromatography on a column of Sepharose coupled with monoclonal antibodies to protein C. The antibodies used were conformation-specific monoclonal antibodies to the calcium-induced structure of protein C. Protein C was bound to antibodies coupled with Sepharose in the presence of calcium ions and was eluted with EDTA. This immunopurification resulted in a 13,000-fold purification of the fully functional zymogen from plasma. The immunoaffinity-isolated protein C was found to have higher amounts of single-chain protein C than conventionally isolated protein C when analyzed by sodium dodecyl sulfate-polyacrylamide gels under reduced conditions. The factor IX concentrate was applied to this Ca2+-dependent antibody JTC-3-immobilized Sepharose in the presence of 5 mM CaCl2, and protein C with its gamma-carboxyglutamic acid (Gla) domain intact was firstly bound to this column and then eluted by metal chelation with EDTA. When flow-through fractions were applied again in the presence of Ca2+ to this column, modified protein C which had lost its N-terminal 42-residue peptide was weakly bound to this column. It was eluted in the absence of Ca2+. However, only a low percentage of modified protein C was detectable by an enzyme-linked immunosorbent assay using Ca2+-dependent monoclonal antibody JTC-3 and peroxidase-labeled immunopurified polyclonal antibody. These results indicate that factor IX concentrate has both Gla-domain-intact and Gla-domainless protein C. Moreover, it suggests that Ca2+-dependent monoclonal antibody JTC-3 may recognize the coupled conformational change of protein C induced by the combined effect of Ca2+ binding to the Gla domain and to other parts of protein C.
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PMID:Immunoaffinity purification of protein C by using conformation-specific monoclonal antibodies to protein C-calcium ion complex. 362 Apr 98

The protease from Southern Copperhead venom that activates protein C was purified to homogeneity by sulfopropyl (SP)-Sephadex C-50 ion-exchange chromatography, Sephadex G-150 gel filtration, and Mono-S fast protein liquid chromatography. The purified enzyme is a glycoprotein containing 16% carbohydrate, and migrated as a single band in sodium dodecyl sulfate-polyacrylamide gel electrophoresis with an apparent molecular mass of 40,000 kDa. The enzyme is composed of a single polypeptide chain possessing an NH2-terminal sequence of Val-Ile-Gly-Gly-Asp-Glu-Cys-Asn-Ile-Asn-Glu-His. The purified venom protein C activator hydrolyzed several tripeptide p-nitroanilides. The amidolytic and proteolytic activities of the enzyme were readily inhibited by phenylmethanesulfonyl fluoride, p-amidinophenylmethanesulfonyl fluoride, chloromethyl ketones, and human antithrombin III. Covalent binding of diisopropyl fluorophosphate to the enzyme was confirmed using a tritium-labeled preparation of the inhibitor. The venom protease readily activated human and bovine protein C at 1:1000 enzyme:substrate weight ratio. The protease also cleaved human prothrombin, factor X, factor IX, factor VII, and fibrinogen. Prothrombin coagulant activity decreased upon incubation with the venom protease, and the rate of this reaction was reduced in the presence of calcium. Factor X and factor IX coagulant activity increased upon incubation with the venom protease in the presence of calcium, and decreased in the absence of calcium. Human factor VII clotting activity decreased slightly upon incubation with the venom protease. Although the venom protease did not clot human fibrinogen, it nonetheless cleaved the A alpha chain of fibrinogen, and this cleavage appeared to be associated with a measurable increase in the clottability of the protease-treated fibrinogen by thrombin. These data demonstrate that the protein C activator from Southern Copperhead venom is a typical serine protease with a relatively broad specificity.
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PMID:Characterization of a protein C activator from Agkistrodon contortrix contortrix venom. 362 72

Homologous "propeptide" regions are present in a family of vitamin K-dependent mammalian proteins, including clotting factors II, VII, IX, X, protein C, protein S and bone "gla" proteins. To test the hypothesis that the propeptide is a signal for the correct gamma-carboxylation of the adjacent gamma-carboxy region, we have mutated amino acid -4 of human factor IX from an arginine to a glutamine residue, by M13-directed site-specific mutagenesis of a cDNA clone. After expression of mutant factor IX in dog kidney cells, we find that it is secreted into the medium in a precursor form containing the propeptide, and is inefficiently gamma-carboxylated compared to the control, wild-type, recombinant factor IX. This result supports the hypothesis that the propeptide region is required for efficient gamma-carboxylation of factor IX in dog kidney cells. Furthermore, it confirms previous results that arginine at amino acid -4 is required for correct propeptide processing.
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PMID:The propeptide region of clotting factor IX is a signal for a vitamin K dependent carboxylase: evidence from protein engineering of amino acid -4. 368 2

The three-dimensional structure of bovine prothrombin fragment 1 has been solved at 2.8-A resolution. The electron density clearly reveals four disulfide bridges along with more than 80% of the side chains completely in density, which correspond faithfully to the kringle sequence, its preceding 30 residues, and the dodecapeptide carboxy terminal; the polysaccharide and the first 35 residues of the amino terminal of fragment 1 are disordered or about 40% of the structure. The folding of the kringle sequence is based upon close disulfide van der Waals contacts between Cys-87-Cys-127 and Cys-115-Cys-139 (4.1 A between midpoints of the bridges), two antiparallel strands of highly conserved (113-118, 124-129) beta-structure, and the stacking of some conserved aromatic residues, all near the center of the folded structure. Moreover, the overall folding appears to be duplicated as a pair of stacked duplex loops with an antiparallel open loop. The overall shape of the kringle structure approximates an eccentric oblate ellipsoid of dimensions 11 X 28 X 30 A. The residues immediately preceding the kringle are dominated by alpha-helical structure (Phe-41-Cys-48; Leu-56-Glu-63). Residues Phe-41-Trp-42 and Tyr-45, which are conserved in factor IX, factor X, protein C, and protein Z, form another aromatic stacked cluster while the Cys-48-Cys-61 disulfide loop corresponds to the well-known alpha/beta structural unit. The dodecapeptide carboxy-terminal interkringle chain extends along the periphery of the kringle in its plane and forms a beta-structure with the kringle-closing Ser-140-Val-143 tetrapeptide.
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PMID:Three-dimensional structure of the kringle sequence: structure of prothrombin fragment 1. 374 41

Factor X is one of six vitamin K dependent proteins known to be involved in blood coagulation, the others being factor VII, factor IX, prothrombin, protein S, and protein C. In the present studies, recombinant bacteriophage containing overlapping DNA inserts coding for the gene for human factor X have been isolated and characterized. These DNA inserts code for almost the entire gene for factor X, extending from the prepro leader peptide through the 3' noncoding region of the transcription product. The organization of the gene for factor X was established by DNA sequencing to identify the location of the introns and exons in the gene. Seven introns and eight exons were identified and their intron/exon boundaries established. The seven introns interrupt the coding sequence at essentially identical locations in the amino acid sequence as the introns in the genes for human factor IX and protein C. In addition, the introns in the gene for factor X divide the coding sequence into discrete exons that code for potential structural and functional domains of the protein. This information provides strong evidence to support the suggestion that the vitamin K dependent proteins present in plasma have evolved from a single, common gene and that this ancestral gene arose through a process that involved the assembly of small protein coding units of DNA into a single gene.
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PMID:Gene for human factor X: a blood coagulation factor whose gene organization is essentially identical with that of factor IX and protein C. 376 36

This study examines the suitability of four recently characterised monoclonal antibodies (MAbs) for the immunoaffinity purification of human coagulation factor IX (FIX) from plasma concentrates. Initial studies using 125I-FIX indicated that appreciable amounts of bound FIX could be eluted from immobilised MAbs with 0.2 M glycine, 50% ethanediol pH 10 (buffer N). Further studies with FIX concentrates showed that buffer N eluted FIX without compromising the activity of the zymogen. Although FIX was eluted from all four MAbs with this buffer, the best yield (82%) was obtained with MAb ESN-3. ESN-3 bound 40 to 60 iu FIX per mg MAb when immobilised on Sepharose 4B. After washing, column elution with buffer N yielded FIX at 100-200 iu/mg. The purity of the product was confirmed by sodium-dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) and by Western blotting. The product contained no detectable mouse IgG (less than 3%) and less than 1% FII, X, or protein C.
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PMID:Immunopurification of human coagulation factor IX using monoclonal antibodies. 377 93

The vitamin K dependent coagulation factor activities were measured in 63 normal human fetuses from 19 to 28 weeks of pregnancy. These activities were included between 9 to 28 percent of normal adult levels. Prothrombin antigen, factor IX antigen and protein C were also measured. There is a good correlation between prothrombin procoagulant activity and antigenicity, suggesting that low level of these vitamin K dependent proteins in fetuses is probably a consequence of liver immaturity.
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PMID:Vitamin K dependent proteins in fetal hemostasis at mid trimester of pregnancy. 384 Feb 88


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