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 low molecular weight serine protease inhibitor, named trypstatin, was purified from rat peritoneal mast cells. It is a single polypeptide with 61 amino acid residues and an Mr of 6610. Trypstatin markedly inhibits blood coagulation factor Xa (Ki = 1.2 x 10(-10) M) and tryptase (Ki = 3.6 x 10(-10) M) from rat mast cells, which have activities that convert prothrombin to thrombin. It also inhibits porcine pancreatic trypsin (Ki = 1.4 x 10(-8) M) and chymase (Ki = 2.4 x 10(-8) M) from rat mast cells, but not papain, alpha-thrombin, or porcine pancreatic elastase. Trypstatin forms a complex in a molar ratio of 1:1 with trypsin and one subunit of tryptase. The complete amino acid sequence of this inhibitor was determined and compared with those of Kunitz-type inhibitors. Trypstatin has a high degree of sequence homology with human and bovine inter-alpha-trypsin inhibitors, A4(751) Alzheimer's disease amyloid protein precursor, and basic pancreatic trypsin inhibitor. However, unlike other known Kunitz-type protease inhibitors, it inhibits factor Xa most strongly.
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PMID:Kunitz-type protease inhibitor found in rat mast cells. Purification, properties, and amino acid sequence. 326 66

This study was performed on patients (n = 18) suffering from strictly defined hyperdynamic septic shock. Plasma factors (C-reactive protein, acid alpha 1-glycoprotein, fibrinogen, fibrinopeptide A, fibrinogen-fibrin split products, factor XIII, antithrombin III, complement factors C3 and C4, inter-alpha-trypsin-inhibitor and alpha 2-macroglobulin) measured during hyperdynamic septic shock were highly abnormal. The activation and consumption of clotting, fibrinolytic and complement factors due to system-specific proteinases (such as thrombokinase or plasminogen activators) seemed to be intensified by the nonspecific proteolytic activity of granulocytic proteinases probably released by the action of endotoxins. Possible therapeutic measures to maintain the endogeneous defence mechanism against enhanced proteolysis during septic shock are discussed.
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PMID:Disturbances of selected plasma proteins in hyperdynamic septic shock. 618 74

Bikunin is a plasma proteinase inhibitor that has received little attention in the past, probably because its activity towards various proteinases was found to be relatively weak in early work. It was recently discovered, however, that bikunin effectively inhibits a proteinase that seems to be involved in the metastasis of tumour cells--cell surface plasmin--and that a fragment of bikunin inhibits two proteinases of the coagulation pathway--factor Xa and kallikrein. Furthermore, it has been found that bikunin has other properties, such as the ability to modulate cell growth and to block cellular calcium uptake. Most of the bikunin in the blood occurs as a covalently linked subunit of the proteins pre- and inter-alpha-inhibitor. In this form bikunin lacks some of its known activities, and there is evidence that its release by partial proteolytic degradation may function as a regulatory mechanism. Although the physiological function of bikunin still remains to be established, current data suggest that this protein plays a role in inflammation. Further studies could therefore lead to results of therapeutical value.
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PMID:Bikunin--not just a plasma proteinase inhibitor. 1068 49