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:3.4.21.5 (thrombin)
33,306 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Fibrinogen Lille, a congenital dysfibrinogenemia, has been reported to arise from a mutation from Asp to Asn at position 7 of the A alpha chain of human fibrinogen, thereby reducing the thrombin-catalyzed rate of hydrolysis of the Arg(16)-Gly(17) peptide bond of this chain. Synthetic peptides of relevant portions of the wild-type and mutant A alpha chains were prepared, and the thrombin-catalyzed rates of hydrolysis of their Arg(16)-Gly(17) peptide bonds were determined. In addition, transferred NOE measurements were made to deduce their conformations, when complexed to bovine thrombin. The kinetics data showed little difference in the hydrolysis rates between the wild-type and mutant peptides, and the NMR data indicate no difference in the bound conformation of these two peptides. Therefore, electrostatic (or salt-bridge) interactions between Asp(7) and thrombin do not influence the bound conformations of these peptides. Asp(7) may interact with a remote residue of fibrinogen, not present in these synthetic peptides, or there may be additional mutations beyond A alpha (1-20) which have not been detected in fibrinogen Lille. Alternatively, when thrombin binds to fibrinogen at its secondary binding site, its primary (active) site may display different reactivities toward wild-type fibrinogen and fibrinogen Lille.
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PMID:Thrombin hydrolysis of an N-terminal peptide from fibrinogen Lille: kinetic and NMR studies. 158 Dec 97

A thrombotic tendency (venous or arterial) has been reported in some cases of dysfibrinogenemia. We report here the mechanism by which these thrombosis may occur. It may be related either to a defective clot lysis due to a poor reactivity toward fibrinolytic enzymes or to a defective thrombin binding capacity of the abnormal clot. Acquired fibrin clot structure anomalies may also be responsible for a defective thrombolysis.
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PMID:Dysfibrinogenemia and thrombosis. 181 98

Patients with primary systemic amyloidosis (AL) often experience bleeding, and we report a newly recognized coagulation abnormality in AL. Of 103 patients with primary systemic AL studied over 2 years, 41 had prolongation of the thrombin time (range, 25 to 46 seconds; normal, less than 22 seconds) and reptilase time (range, 17 to 39 seconds; normal, 14 to 16 seconds). The fibrinogen from the plasma of 36 patients was precipitated by beta-alanine and diluted to a concentration of approximately 200 mg/dL. The thrombin times of the precipitated fibrinogens were normal in 34 patients, implying that an inhibitor was responsible for the abnormal tests. The addition of patient fibrinogen-free plasma to normal plasma prolonged the thrombin times, and this result confirmed the presence of an inhibitor. The inhibitor is more likely to be present in patients with nephrotic syndrome (20 of our patients) and congestive heart failure (six). A circulating monoclonal protein (24 patients), the presence of amyloid liver involvement (eight), and the presence of amyloid neuropathy (nine) were not predisposing factors. Only one patient had deficiency of factor X. We conclude that inhibition of fibrinogen conversion to a fibrin clot rather than dysfibrinogenemia is the cause of the prolonged thrombin time in primary systemic AL.
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PMID:Inhibitor of the thrombin time in systemic amyloidosis: a common coagulation abnormality. 190 84

A new case of heterozygous dysfibrinogenemia characterized by the replacement of NH2-terminal amino acid of fibrin beta-chain was found in a 50-year-old man. Despite a prolonged thrombin time, the propositus' fibrinogen had a normal reptilase time with the normal release of fibrinopeptide A. Release of fibrinopeptide B by thrombin was strongly affected, but a very high concentration of thrombin almost completely released fibrinopeptide B with a normal elution pattern on reversed-phase high performance liquid chromatography (HPLC). Lysylendopeptidase-cleavage of purified B beta-chains analyzed on HPLC showed the decrease of one peptide compared with the normal and the appearance of an abnormal peptide peak. These peptides were treated with thrombin and further separated on HPLC. Amino acid sequence analysis of the abnormal peptide demonstrated that B beta glycine-15, NH2-terminus of the fibrin beta-chain, was replaced by cysteine. These findings will be of particular importance because they strongly support the hypothesis that the NH2-terminal portion of the fibrin beta-chain is involved in the polymerization reaction by thrombin. The propositus' daughter and two sisters had the same abnormal fibrinogen. This unique inherited abnormal fibrinogen was designated as fibrinogen Ise. During these studies, we found that a very high concentration of thrombin cleaves not only the A alpha Arg19-Val20 bond but also the COOH-terminal region of alpha-chains, which results in the generation of further degraded alpha-chains with apparent molecular weights of 44,000 or less.
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PMID:A new congenital abnormal fibrinogen Ise characterized by the replacement of B beta glycine-15 by cysteine. 201 36

A new case of heterozygous dysfibrinogenemia characterized by an amino acid replacement in the NH2-terminal region of the fibrin alpha-chain was found in a 27-year-old woman with a bleeding problem. Her one-stage prothrombin time and activated partial thromboplastin time were slightly prolonged, and the purified fibrinogen from this patient had a markedly prolonged thrombin or reptilase time. Release of fibrinopeptides A and B was normal, but the polymerization of fibrin monomers was impaired. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the purified fibrinogen under the reduced condition showed no abnormalities in the apparent molecular weights of its three chains. Reverse-phase high performance liquid chromatography (HPLC) of the lysylendopeptidase-cleaved purified A alpha-chains showed a decrease in one peptide compared with the normal amount and the appearance of an abnormal peptide peak. These peptides were treated with thrombin and further separated on HPLC. Amino acid sequence analysis of the abnormal peptide indicated that A alpha proline-18, the second residue from the NH2-terminus of the fibrin alpha-chain, was replaced by leucine. The synthetic peptide Gly-Pro-Arg-Pro inhibited both thrombin- and reptilase-induced fibrin aggregation, but Gly-Leu-Arg-Pro showed little or no inhibition under the same conditions. The discovery of this abnormal fibrinogen supports the findings that A alpha proline-18 is important as part of the polymerization site in the NH2-terminus of the fibrin alpha-chain. The propositus' mother had the same abnormal fibrinogen. This unique inherited abnormal fibrinogen was designated as fibrinogen Kyoto II.
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PMID:Fibrinogen Kyoto II, a new congenitally abnormal molecule, characterized by the replacement of A alpha proline-18 by leucine. 207 49

An abnormal fibrinogen was discovered in the plasma of a clinically asymptomatic woman. Laboratory evaluation of five members of the affected family showed low fibrinogen values in kinetic assays whereas the fibrinogen levels, tested by immunological procedures were normal. The patient's plasma had an inhibitory effect on the thrombin time of normal plasma. The calcium ions totally corrected the thrombin and reptilase times. Either low or high ionic strength prolonged the thrombin time of the proposita's purified fibrinogen. Kinetic analysis of clotting by monitoring transmission at 350 nm showed abnormally slow clotting with thrombin and reptilase. Assays were preformed in whole plasma as well as in purified fibrinogen. A delay in the rate of polymerization was evident when purified patient monomers were compared with those of normals. Immunoelectrophoretic, chromatofocusing, and isoelectrofusing experiments detected neither structural nor immunological abnormalities of fibrinogen. The rate of release of fibrinopeptide A by thrombin, measured by a specific immunoenzymatic method was also normal. HPLC analysis showed normal liberation of fibrinopeptides after prolonged thrombin action. Cross-linking of fibrin by factor XIII and lysis of fibrinogen by plasmin were normal. In view of these results, the defect of this dysfibrinogenemia, designated as Fibrinogen Oviedo I, probably could be due to conformational modifications in the D section of the molecule.
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PMID:Fibrinogen Oviedo I. A new Spanish dysfibrinogenaemia. 213 36

A 38-year-old female with acute lymphoblastic leukemia developed monoplegia of the left upper extremity following chemotherapy for remission induction consisting of vincristine, prednisolone, cyclophosphamide, adriamycin and methotrexate. Hemorrhagic infarction due to thrombosis of the right cortical vein was diagnosed by brain images using computed tomography and magnetic resonance imaging in addition to the clinical course. At this time, a plasma level of fibrinogen measured by the thrombin time method had decreased to 84 mg/dl, while its antigenicity was 276 mg/dl. There was no evidence of activation of the blood coagulation and fibrinolysis system nor of abnormal liver function. A mixing test with normal plasma disclosed the absence of an inhibitory factor against fibrin polymerization in her plasma. Fibrinogen levels as assessed by the thrombin time method recovered to the antigenicity level one and half months later. The discrepancy between the activity and antigenicity of fibrinogen indicated the occurrence of acquired dysfibrinogenemia, probably induced by antileukemic agents. Thus, it is suggested that dysfibrinogenemia is a possible cause of cerebral thrombosis in this patient.
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PMID:[Transient dysfibrinogenemia and cerebral thrombosis following remission induction therapy for acute lymphoblastic leukemia]. 224 26

We describe a new congenital dysfibrinogenemia: fibrinogen Barcelona II in 8 members of a family with no major bleeding or thrombotic tendency. Incubation of this fibrinogen with thrombin at low concentration releases half of the expected normal fibrinopeptide A (FPA) and with some delay it releases an abnormal FPA. Abnormal FPA was purified and sequenced and showed a change in the normal amino acid sequence: arginine in position 16 has been substituted by a histidine. This is another case of dysfibrinogenemia in which A alpha 16 Arg----His has been identified as the cause of abnormal behavior of the fibrinogen molecule.
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PMID:Fibrinogen Barcelona II: a new case of A alpha 16 Arg----His substitution. 232 78

Congenital heterozygous dysfibrinogenemia was diagnosed in a young woman with bleeding tendency. 3 other asymptomatic members of her family (mother and the 2 sisters) had abnormal fibrinogen. The proposita's plasma exhibited prolonged thrombin and reptilase times. Plasma fibrinogen concentration determined by functional assay was 0.3 g/l, whereas immunologic assay revealed normal fibrinogen levels. Turbidity curves, representing the rate of thrombin-induced fibrin formation, were markedly delayed both in the presence and absence of Ca2+. Isoelectric focusing and SDS electrophoresis of reduced fibrinogen showed normal charge and size of the subunit chains. Release of fibrinopeptide B by thrombin was normal, whereas HPLC elution diagrams of fibrinopeptide A showed an abnormal peak A* with a slightly shorter retention time than the normal fibrinopeptide A. The amino acid analysis showed that the arginine in peak A* is replaced by histidine (A alpha 16 Arg----His).
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PMID:Fibrinogen Milano. VI: A heterozygous dysfibrinogenemia (A alpha 16 Arg----His) with bleeding tendency. 237 62

Congenital dysfibrinogenemia was found in a 60-year-old asymptomatic female and her daughter. Purified fibrinogen derived from the propositus, apparently a heterozygote for the abnormality, characteristically showed delayed but complete release of fibrinopeptide A upon digestion with thrombin but its defective release by Ancrod, a snake venom enzyme, from half of her fibrinogen molecules. This congenital dysfibrinogenemia with an A alpha arginine (Arg) to histidine (His) substitution was tentatively designated as fibrinogen Sapporo. Although this type of abnormal fibrinogen had been identified among Caucasians, no such cases have so far been reported in Japan.
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PMID:Fibrinogen Sapporo: dysfibrinogenemia characterized by the replacement of A alpha arginine-16 by histidine resulting in the delayed release of fibrinopeptide A by thrombin. 258 59


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