Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.4.21.6 (thromboplastin)
13,278 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A strong inhibitor of human Hageman factor fragment (HFf, beta-factor XIIa) and bovine trypsin was isolated from pumpkin (Cucurbita maxima) seed extracts by acetone fractionation, by chromatography on columns of diethyl-aminoethylcellulose and carboxylmethyl-Sephadex C-25, and by Sephadex G-50 gel filtration. Pumpkin seed Hageman factor inhibitor (PHFI) is unusual in its lack of inhibition of several other serine proteinases tested--human plasma, human urinary, and porcine pancreatic kallikreins, human alpha-thrombin, and bovine alpha-chymotrypsin. Human plasmin and bovine factor Xa are only weakly inhibited. PHFI also inhibits the HFf-dependent activation of plasma prekallikrein and clotting of plasma. Other properties of PHFI are a pI of 8.3, 29 amino acid residues, amino-terminal arginine, carboxyl-terminal glycine, 3 cystine residues, undetectable sulfhydryl groups and carbohydrate, and arginine at the reactive site. The minimum molecular weight of PHFI is 3268 by amino acid analysis. PHFI may be the smallest protein inhibitor of trypsin known.
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PMID:Pumpkin seed inhibitor of human factor XIIa (activated Hageman factor) and bovine trypsin. 621 35

A 42-yr-old woman with systemic lupus erythematosus without bleeding diathesis developed a prolonged activated partial thromboplastin time that was not corrected by normal plasma. An inhibitor that acted rapidly and inactivated 0.5 U/ml plasma thromboplastin antecedent (PTA, factor XI) at a 1:200 plasma dilution was demonstrated. In addition to a low titer of PTA (less than 0.01 U/ml), plasma assayed at 20-fold dilution also showed low titers of Hageman (factor XII, 0.02 U/ml), Fletcher (plasma prekallikrein, 0.02 U/ml), and Fitzgerald (high molecular weight kininogen, less than 0.01 U/ml) factors. The titer of these factors, except PTA, returned to normal upon further plasma dilution or upon removal of the inhibitor by protein A adsorption. Thus, the inhibitor appeared to interfere with these clotting factor assays, possibly by inactivating PTA in the substrate plasmas in the test system. Its specificity was further confirmed. The inhibitor did not interfere with surface-induced proteolytic cleavage of Hageman factor. Surface-induced generation of plasma kallikrein activity (amidolysis of H-D-pro-phe-arg-pNa and cold-promoted factor VII activity enhancement) requires only Hageman, Fletcher, and Fitzgerald factors and was normal. Reactions requiring all 4 contact phase factors, including PTA, such as surface-induced generation of plasmin activity (amidolysis of H-D-val-leu-lys-pNa) and activated Christmas factor (factor IXa) activity, were defective. Furthermore, the inhibitor bound to agarose-protein A inactivated and removed PTA selectively from normal plasma. The inhibitor was an IgG-lambda autoantibody that precipitated PTA. The inactivated activated PTA (factor XIa) without the requirement for an additional cofactor. Furthermore, it inhibited surface-induced activation of PTA by interfering with its proteolytic cleavage upon glass surface exposure and with its binding onto the reactive surfaces.
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PMID:A unique precipitating autoantibody against plasma thromboplastin antecedent associated with multiple apparent plasma clotting factor deficiencies in a patient with systemic lupus erythematosus. 642 50

The intramuscular or intravenous administration of ISG prepared from human plasma by ethanol fractionation can elicit such reactions as pain at the injection site, flushing, and even hypotension. Similar adverse reactions to plasma protein fraction, a volume expander also made by ethanol fractionation, have been associated with PKA (Hageman factor fragments) in the product. Twenty-five lots of commercial ISG were therefore analyzed for PKA and kallikrein, components of the contact activation system which could mediate such reactions through the generation of kinins in recipients. Kallikrein activity ranged from undetectable levels to > 60% of the total potential kallikrein activity in normal plasma. PKA, which was measured by its ability to catalyze the conversion of prekallikrein to kallikrein, ranged from 5% to 3950% of the activity in a reference plasma protein fraction that had caused hypotension. All but five lots increased vascular permeability in the guinea pig. The five lots which caused no increased were also the lowest in PKA and kallikrein activity. When ISG ws subjected to gel chromatography to separate the enzymic contaminants from immunoglobulin G, only the fractions containing PKA and/or kallikrein increased vascular permeability. Several lots of ISG shortened the nonactivated partial thromboplastin time of normal plasma fro 236 sec to 38 to 55 sec. During gel chromatography, coagulation activity was eluted in a position corresponding to a molecular weight of 150,000; it was inhibited by antibody to human factor XI. These data indicate that factor XIa is responsible for the coagulant activity observed and that PKA and/or kallikrein are potential mediators of vasoactive reactions to ISG.
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PMID:Contact-activated factors: contaminants of immunoglobulins preparations with coagulant and vasoactive properties. 644 81

Fibrin clots have been detected at sites of inflammation, and kinins have been implicated as mediators of the vascular phenomena of acute inflammation, systemic shock, and disseminated intravascular coagulation. It is now reported that both negatively and positively charged asbestos fibers shorten the partial thromboplastin time of human plasma, indicating coagulation of the plasma. A sample containing short (less than 5 micron in length) chrysotile fibers is ineffective. Only the negatively charged amphiboles (crocidolite and amosite) are able to activate factor XII (Hageman factor). This particular effect of the amphiboles is enhanced by high molecular weight kininogen and leads to kinin formation.
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PMID:Asbestos fibers, plasma and inflammation. 664 59

A patient with factor XII deficiency, gout, and angioimmunoblastic lymphadenopathy (AIL) was seen initially for an acute myocardial infarction, gout, and unexplained urticaria. The patient eventually was found to have AIL and a prolonged partial thromboplastin time. There was no evidence of a circulating anticoagulant. A factor XII deficiency (Hageman factor) was discovered. The coexistence of a factor XII deficiency, AIL, and gout in the same person raises some interesting questions regarding the basic mechanisms of the inflammatory process.
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PMID:Factor XII deficiency in a man with gout and angioimmunoblastic lymphadenopathy. 673 12

Activation of bovine plasma prekallikrein was investigated with several proteinases. Highly purified bovine plasma prekallikrein was rapidly activated to kallikrein [EC 3.4.21.8] by bovine activated Hageman factor, trypsin [EC 3.4.21.4] and Pronase P (proteinases from Streptomyces griseus) and more gradually by papain [EC 3.4.22.2] and ficin [EC 3.4.22.3]. Activation of prekallikrein was also observed with bovine plasmin [EC 3.4.21.7], but not with bovine clotting factors Xa (Stuart factor) [EC 3.4.21.6] and IXa (Christmas factor) or thrombin [EC 3.4.21.5]. Urokinase [EC 3.4.99.26], Reptilase, collagenase [EC 3.4.24.3], elastase [EC 3.4.21.11], alpha-chymotrypsin [EC 3.4.21.1], Nagarse [EC 3.4.21.14], and stem bromelain [EC 3.4.22 4] did not convert prekallikrein to kallikrein. Plasma kallikrein activated to Hageman factor released kinin rapidly from bovine high molecular weight (HMW) kininogen. However, from bovine low molecular weight (LMW) kininogen, liberation of kinin was extremely slow. The kallikrein activity was inhibited by soybean trypsin inhibitor (SBTI), Trasylol, diisopropylfluorophosphate (DFP), and N-alpha-tosyl-L-lysine chloromethylketone (TLCK), but not by egg-white trypsin inhibitor (EWTI), lima bean trypsin inhibitor (LBTI), heparin or hexadimethrine bromide (Polybrene). The kallikrein formed an enzyme-inhibitor complex with SBTI and Trasylol, but not with LBTI. Prekallikrein did not react with SBTI. Prekallikrein consists of a single polypeptide chain of molecular weight about 90,000, as estimated by sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis. Activation of prekallikrein by Hageman factor was found to involve cleavage of the single peptide bond on the disulfide-bridged polypeptide chain, and no change of molecular weight was observed during the activation. The peptide bond cleaved in prekallikrein by the activation was an Arg-X peptide bond on a disulfide-bridged polypeptide chain.
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PMID:Studies on prekallikrein of bovine plasma. II. Activation of prekallikrein with proteinases and properties of kallikrein activated by bovine Hageman factor. 676 24

A case of cross-reacting material-negative Fletcher trait with additional partial deficiency of Hageman factor (HF, Factor XII) is described. Although the patient presented with a recent history of frequent epistaxis, he had no other personal or family history of a tendency toward bleeding or infection. Similar to other cases of Fletcher trait, his plasma showed a markedly prolonged partial thromboplastin time which could be corrected by prolonged incubation with the surface-activator kaolin. Surface-induced fibrinolysis, amidolysis of alpha-N-benzoyl-proline-L-phenylalanine-L-arginine-p-nitroanilide, and cold-promoted enhancement of factor VII activity, reactions requiring the presence in the plasma of fletcher factor (prekallikrein), in addition to Hageman factor and Fitzgerald factor (high-molecular weight kininogen), were also defective. In vivo chemotaxis of polymorphonuclear leukocytes and monocytes (Rebuck's skin window technique) in response to skin abrasions was defective, but was normal when diphtheria-tetanus toxoid was also applied. In vitro leukocyte chemotaxis (Boyden chamber technique) in response to normal or patient's own serum activated with zymosan was normal. Together with previous observations that kallikrein generated chemotactic activity, possibly via activation of C5, the present observations suggest that prekallikrein activation may be important for in vivo leukocyte chemotactic response to skin abrasion. The inheritance of Fletcher trait in this patient is unclear.l Although the father was an apparent heterozygote, the mother was completely normal for Fletcher factor procoagulant activity and antigen. The mild Hageman factor deficiency in the patient did not contribute significantly to the plasma defects described and was likely inherited from the father who had a low HF procoagulant activity.
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PMID:Severe Fletcher factor (plasma prekallikrein) deficiency with partial deficiency of Hageman factor (factor XII): report of a case with observation on in vivo and in vitro leukocyte chemotaxis. 691 94

Factor XII plasma levels were investigated with several methods in patients with hemophilia A and B and von Willebrand syndrome. There seem to be some families with hemophilia A or von Willebrand syndrome, who have an additional, congenital, partial lack of factor XII (Hageman factor). The mode of inheritance is independent of the other coagulation disorder. Frequently, the first indication of an additional factor XII deficiency is the disproportionate prolongation of the activated partial thromboplastin time (PTT) as regards the factor VIII level. The average factor XII level in patients with hemophilia A and von Willebrand syndrome is significantly lower than in normal subjects or patients with hemophilia B. It cannot be excluded that the frequently low levels of factor XII in patients with severe hemophilia are acquired and probably due to liver cell damage.
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PMID:Additional factor XII (Hageman factor) deficiency in hemophilia A and in von Willebrand syndrome. 697 68

Prolonged extracorporeal circulation (ECC) using heparin as anticoagulant may be associated with pronounced thrombocytopenia and excessive bleeding. We, therefore, tested the hypothesis that reversible inhibition of platelet function, in lieu of heparinization, might preserve platelets and prevent coagulation in a perfusion circuit. When 500 ml of fresh heparinized (one U/ml) human blood was recirculated in a perfusion circuit constructed of standard silicone rubber components and a membrane oxygenator (0.95 M2), platelet counts declined to 9 +/- 2 (SEM) % of initial levels within 15 mins; plasma levels of the platelet specific protein LA-PF4 rose to 15 +/- 2 micrograms/ml within one hour indicating extensive release of platelet granule contents, and leukocyte counts declined to 91 +/- 4% within 15 mins. Prostacyclin (PGI2, greater than or equal to 25 eta M) or prostaglandin E1 (20 microM) and theophylline (12 mM) prevented platelet loss and release of granule contents. When heparin was reversed with protamine, however, immediate coagulation ensured. This occurred despite the absence of detectable activation of Hageman factor as evidenced by stability of plasma concentrations of prekallikrein in systems anticoagulated with heparin or citrate and despite our inability to detect thromboplastin-like properties in isolated leukocytes. Thus, coagulation in the presence of platelet inhibition suggests that alternative pathways, independent of platelet activation may exist. Platelet inhibition does preserve platelets preventing contact initiated release, but cannot serve by itself for anticoagulation.
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PMID:Prostacyclin in lieu of anticoagulation with heparin for extracorporeal circulation. 703

A 62-year-old man with a typical history of gout was admitted to the hospital with left-sided hemiplegia. His serum uric acid level was 10.3 mg/dL, his partial thromboplastin time was 198 s, and his Hageman factor (factor XII) coagulant activity and antigen were less than 1% of normal. Aspiration of synovial fluid from his inflamed knee disclosed urate crystals and abundant leukocytes but an absence of Hageman factor antigen. The presence of acute gouty arthritis in a patient with Hageman trait challenges the role of Hageman factor in the pathogenesis of gouty arthropathy.
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PMID:Classic gout in Hageman factor (Factor XII) deficiency. 710 39


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