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)

Bovine platelets that have been activated by thrombin facilitate the conversion of prothrombin to thrombin in the presence of calcium ions and factor Xa. Activated protein C, a vitamin-K-dependent plasma protein, inhibits this platelet prothrombin-converting activity. The inhibition is time dependent and is not reversed by increasing concentrations of factor Xa. However, factor Xa is able to protect the platelet prothrombin-converting activity from inactivation by activated protein C. The activated protein C causes a parallel loss of factor Xa receptor sites and platelet prothrombin-converting activity. Activated protein C may contribute to the regulation of clotting through inactivation of the platelet prothrombin-converting activity.
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PMID:Activated protein C inhibits platelet prothrombin-converting activity. 50 37

The serum concentration of protein SAP (amyloid P component) has been measured for the first time in a substantial series of normal individuals and patients with various diseases, and the results contrasted with the levels of the related protein C-reactive protein (CRP). The mean +/- s.d. concentration of protein SAP was 43 +/- 14 microgram/ml in seventy-six normal men, 33 +/- 10 microgram/ml in eighty-six normal women and 4 +/- 2 microgram/ml in thirty-six normal cord sera. Unlike CRP, whick is a major acute phase reactant, protein SAP was only slightly elevated in inflammatory and neoplastic diseases in which CRP was greatly increased. The level of protein SAP was significantly depressed in patients with hepatic disease, suggesting that its measurement might be of value in their management.
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PMID:Comparative clinical study of protein SAP (amyloid P component) and C-reactive protein in serum. 66 89

Platelet-rich plasma from dogs and from coumadin-treated dogs aggregated at the same optimum concentration of epinephrine. Neither protein C nor its active form called autoprothrombin II-A was necessary for aggregation of dog platelets with epinephrine. For platelet aggregation, suboptimal concentrations of epinephrine were potentiated by addition of purified autoprothrombin II-A. The latter, by itself, induced platelet aggregation in high concentration.
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PMID:Effects of autoprothrombin II-A on epinephrine-induced platelet aggregation of normal- and coumadin-treated dogs. 72 51

Two major proteins, termed proteins A and B, and one minor species, termed protein C, have been purified to homogeneity from dilute acid extracts of dormant spores of Bacillus megaterium. These three species comprise approximately 80% of the protein in the dilute acid extracts and account for 60 to 75% of the protein degraded during spore germination. All three proteins have low molecular weights (7,000 to 10,000), high isoelectric points (greater than 9.8), alanine as the NH2-terminal amino acid, are more hydrophilic than most proteins, and all lack cysteine, cystine, and tryptophan. In addition all three proteins are extremely sensitive to a wide variety of proteolytic enzymes, much more so than "average" proteins such as serum albumin, lysozyme, and hemoglobin. These proteins also bind to both purified DNA and to a nuclear body from dormant spores. Although this binding gives little or no protection to proteins A and B from proteolysis, it does result in elevation of the melting temperature of the DNA by as much as 20degrees.
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PMID:Purification and properties of some unique low molecular weight basic proteins degraded during germination of Bacillus megaterium spores. 80 43

The isolation of a highly purified phosphoprotein, previously named protein C, from human parotid saliva is described. A chemical and physical characterization of protein C was undertaken and the properties of protein C were compared with those of a related protein A. The content of glycine, proline and dicarboxylicamino acids accounts for 83% of the total resideus of protein C and it contains 2.0 mol of P/mol of protein, most likely as phosphoserine. The protein also contains 1.2% glucose, but no hexosamine. The N-terminus is blocked and the proposed C-terminal sequence is -Ser(Gly, Pro)Gln. The molecular weight determined from ultracentrifugation is 16300. Circular dichroism and nuclear magnetic resonance fail to demonstrate the presence of polyproline structure, and there are no conformational changes under a variety of conditions. With specific antisera to protein C the protein can be detected in submandibular as well as in parotid saliva, but there is only reaction of partial identity of proteins A and C. It is proposed that at least part of the difference between proteins A and C is due to the presence of an additional length of peptide at the C-terminus of protein C.
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PMID:Chemical and physical characterization of a phosphoprotein, Protein C, from human saliva and comparison with a related protein A. 86 25

Protein C is a vitamin K dependent protein present in bovine plasma (Stenflo, J. (1976), J. Biol. Chem. 251, 355). It is a glycoprotein (mol wt approximately 62 000) composed of a heavy chain (mol wt 41 000) and a light chain (mol wt 21 000). The heavy chain has an amino-terminal sequence of Asp-Thr-Asn-Gln and contains nearly three-fourths of the carbohydrate. The light chain has an amino-terminal sequence of Ala-Asn-Ser-Phe. Incubation of protein C with either factor X activator from Russell's viper venom or trypsin resulted in the cleavage of an Arg-Ile bond between residues 14 and 15 of the heavy chain. Concomitant with this cleavage was the formation of a serine enzyme which was inhibited by diisopropyl phosphorofluoridate. Liberation of the tetradecapeptide decreased the molecular weight of the heavy chain from about 41 000 to 39 000 and resulted in the formation of a new amino-terminal sequence of Ile-Val-Asp-Gly in the heavy chain. No change in the molecular weight of the light chain was observed during the activation reaction. These results indicate that protein C, like the four vitamin K dependent coagulation proteins, exists in plasma in a precursor form and is converted to a serine protease by hydrolysis of a specific Arg-Ile peptide bond. The biological substrate for the enzymatic form of protein C and the physiological mechanism whereby protein C is converted to a serine enzyme are not known.
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PMID:Proteolytic activation of protein C from bovine plasma. 99 Feb 50

The protease from Russell's viper venom that activates factor X (Stuart factor), factor IX (Christmas factor), and protein C was purified by gel filtration on Sephadex G-150 and QAE-Sephadex A-50 column chromatography. The purified enzyme migrated as a single band in sodium dodecyl sulfate-polyacrylamide gel electrophoresis with an apparent molecular weight of 79 000. A minimal molecular weight of 78 500 +/- 800 was determined by sedimentation equilibrium in the presence of 6 M guanidine hydrochloride. Upon reduction with 2-mercaptoethanol, a heavy chain (mol wt 59 000) and a light chain were observed. The light chain migrated as a single band (mol wt 19 000) in 7.5% polyacrylamide-sodium dodecyl sulfate gels but appeared as a doublet (mol wt 18 000 and 20 000) in 10% polyacrylamide-sodium dodecyl sulfate gels. The amino-terminal end of the heavy chain was heterogeneous and contained isoleucine, valine and serine. The amino-terminal sequence of the light chain was Val-Leu-Asp. The factor X activator contained 13% carbohydrate including 6.0% hexose, 1.7% N-acetyleneuraminic acid, and 5.3% galactosamine. Most of the carbohydrate was found to be present in the heavy chain, although some was also observed in both forms of the light chain. The factor X activator had no esterase activity toward benzoyl-Phe-Val-Arg-p-nitroanilide or benzoylarginine ethyl ester and was not inhibited by 0.05 M diisopropyl phosphorofluoridate. These data indicate that factor X activator from Russell's viper venom is a highly specific protease composed of one heavy chain and one light chain, and these chains are held together by a disulfide bond(s).
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PMID:Factor X activating enzyme from Russell's viper venom: isolation and characterization. 99 Feb 51

Reactional leprosy is studied according to its clinical forms A) Lepromatous a) Acute lepromatization: encroaching and invasive nature; the patient becomes more and more lepromatous ; bad prognosis. b) Erythema nodosum: "contusiform dermatitis"; variable prognosis not so bad as it is in the preceding case; allergic nature and its evolution is usually detained and therapeutics efficient. c) Erythema multiform. d) Lucio's phenomenon: vascular lesions and consequently necrosis as a complication of the "erythema necrotisans" (beautiful leprosy). B) Tuberculoid Reactional tuberculoid is the only one in this benign type, the Mitsuda's test must always be positive and prognosis consequently good. C) Dimorphous or "Borderline" whose Mitsuda's test is mostly negative, sometimes positive, but not stable. The lesions may stimulate the tuberculoid leprids but they invade mucous membranes, are impregnated by pigmentation, may present the Unna's band, and other characteristics of the Lepromatous type. Are associated (fever, asthenia and emaciation). Prognosis not very good, because of the possibility of lepromatization, according to its tendency. Evolution slower and frequent relapses. Besides there are nodular lesions. Pathogeny 1) Perifocal allergic reaction (Jadassohn). Similar to epituberculosis and Herxheimer reaction. 2) Septicemia. Sensitized tissues inside or outside the lesions, are invaded by the bacilli and so the allergic reaction takes place. Even without culture resources, Mycobacterium leprae has been found in the blood by direct examination. 3) Autoimmunization (Waldenstrom, Matthews and Trantman, 1965). Based upon the similarity between both humoral syndromes, in leprosy reactions and collagenous, diseases, as to: hypergammaglobulins, hypercryoproteins, antigammaglobulins, serological reactions (Wassermann, Kahn, Kline, VDRL) positives, Antistreptolysin O, protein C reactive, antinuclear factors, latex and Wadler-Rose test positives (rheumatoid tests) lowering of complement. If leprosy reaction is like this, it should be the less agressive of the autoimmune diseases. a) Its eruptions are cyclic not of long standing duration, as a general rule. b) Its prognosis has been recognized as good, except lately, because of the use of corticoid therapy which has been fatal, in many cases. After some years the leprosy reaction cures spontaneously. Treatment (see article)
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PMID:[Reactional status of leprosy]. 124 Oct 72

Plasma from women taking combined oral contraceptives and cold-activated plasma contain proteases which cleave chromogenic substrates in protein C assays in the absence of protein C activators such as Protac. This spontaneous activity makes a background substraction necessary and makes protein C (PC) assays less accurate. We investigated two commonly used substrates < Glu-Pro-Arg-pNA (S-2366) and 2AcOH.H-D-Lys(Cbo)-Pro-Arg-pNA (PC substrate) and found that cold-activated normal and protein C-deficient plasmas gave absorbance values up to 300 times higher than buffer blanks. FXIa cleaves these substrates but activity was not blocked by corn or lima bean trypsin inhibitors, soy bean trypsin inhibitor (SBTI), hirudin or epsilon-amino-n-caproic acid (EACA). Kaolin activation of normal, FXI, FIX, FVIII, FVII and protein C-deficient, but not of FXII or prekallikrein (PKK)-deficient plasmas led to cleavage of chromogenic substrate for protein C. The protein C substrates were cleaved by purified kallikrein and alpha- and beta-FXIIa. Immunoabsorption with alpha 2-macroglobulin (alpha 2M) antibodies removed 60% of the alpha 2M and 70% of the activity on PC Substrate. Gel filtration of normal plasma on Sephadex G-150 gave a single peak of protein C activity and antigen in the included volume. After cold activation of the fractions, a second protein C-like peak appeared in the void volume, but with no detectable protein C antigen. This peak coincided with alpha 2M (chromogenic and ELISA) and plasma kallikrein (S-2302), but FXII (measured with a substrate insensitive to kallikrein) eluted separately.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Contact factor proteases and the complexes formed with alpha 2-macroglobulin can interfere in protein C assays by cleaving amidolytic substrates. 128 Apr 70

A consumption coagulopathy syndrome has frequently been reported in association with some cases of acute nonlymphoblastic leukemia (ANLL) and mainly in acute promyelocytic leukemia (M3). Eighteen cases of ANLL have been studied on admission, before chemotherapy was started. Levels of antithrombin III (AT-III), protein C (PC), protein S (PS), thrombin-antithrombin complex (T-AT-III), tissue plasminogen activator, plasminogen (Pg), alpha-2-antiplasmin (alpha-2-AP), D-dimer (DD) and fibrinogen (Fg) were determined. The results showed normal levels of AT-III and PS, decreased levels of PC, alpha-2-AP, Pg and Fg in some cases, and an elevation of DD and T-AT III complex in almost all patients. There was a continuous evolution of data from M1 cases in which only slight alterations were seen up to M3 cases where all those pathologic data were observed.
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PMID:A continuous spectrum of hypercoagulability exists in acute nonlymphoblastic leukemia. 128 98


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