Complete inhibition of fibrinolysis by sustained carboxypeptidase B activity: the role and requirement of plasmin inhibitors

SummaryA new method for the assay of plasmin inhibitors in human plasma is described. The method consists of determination of the caseinolytic activity of a standard plasmin solution before and after incubation with the inhibitor, with lysine added to the mixture as a stabilizer of plasmin. Using this method, it was found that plasma contains enough inhibitors to inactivate 30 caseinolytic units of plasmin, or 10 times the normal amount of plasminogen in human plasma.

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Low Molecular Weight Trypsin-Plasmin Inhibitors Isolated from Papain Treated Urinary Trypsin Inhibitor

Thrombosis and Haemostasis ◽

10.1055/s-0038-1657115 ◽

1982 ◽

Vol 47 (01) ◽

pp. 014-018 ◽

Cited By ~ 13

Author(s):

H Sumi ◽

N Toki ◽

S Takasugi ◽

S Maehara ◽

M Maruyama ◽

...

Keyword(s):

Trypsin Inhibitor ◽

Gel Electrophoresis ◽

Specific Activity ◽

Polyacrylamide Gel Electrophoresis ◽

Sodium Dodecyl ◽

Gel Chromatography ◽

Urinary Trypsin Inhibitor ◽

Plasmin Activity ◽

Molecular Weights ◽

Plasmin Inhibitors

SummaryPapain treatment of human urinary trypsin inhibitor (UTI67; mol. wt. 43,000 by SDS-polyacrylamide gel electrophoresis, specific activity 1,897 U/mg protein) produced four new protease inhibitors, which were highly purified by gel chromatography on Sephadex G-100 and isoelectric focusing. The purified inhibitors (UTI26, UTI9-I, UTI9-II, and UTI9-III) were shown to be homogeneous by polyacrylamide disc gel electrophoresis, and had apparent molecular weights of 26,000, 9,000, 9,000, and 9,800, respectively, by sodium dodecyl sulfate gel electrophoresis. During enzymatic degradation of UTI67, the amino acid compositions changed to more basic, and the isoelectric point increased from pH 2.0 (UTI67) to pHs 4.4, 5.2, 6.6, and 8.3 (UTI26, UTI9-I, UTI9-II, and UTI9-III), respectively. Both the parent and degraded inhibitors had anti-plasmin activity as well as antitrypsin and anti-chymotrypsin activities. Much higher anti-plasmin/anti-trypsin and anti-plasmin/anti-chymotrypsin activities were observed in the degraded inhibitors than in the parent UTI67. They competitively inhibited human plasmin with Ki values of 1.13 X 10-7 - 2.12 X 10-6 M (H-D-Val-Leu-Lys-pNA substrate). The reactions were very fast and the active site of the inhibitors to plasmin was thought to be different from that to trypsin or chymotrypsin.

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Human Platelet Acetylcholinesterase: The Effects of Anticholinesterases on Platelet Function

Thrombosis and Haemostasis ◽

10.1055/s-0038-1657065 ◽

1979 ◽

Vol 42 (05) ◽

pp. 1615-1619 ◽

Cited By ~ 1

Author(s):

Martin J Smith ◽

Boyd Braem ◽

Kent D Davis

Keyword(s):

Platelet Function ◽

Ache Activity ◽

Room Temperature ◽

Platelet Rich Plasma ◽

Complete Inhibition ◽

Clot Retraction ◽

Plasma Clot ◽

Normal Platelet ◽

Aggregation Factor

SummaryPlatelet acetylcholinesterase (AChE) activity was measured in gel-filtered platelet preparations. Three different anticholinesteratic agents (eserine, neostigmine, and diiso- propylphosphorofluoridate) at final concentrations of 10 μM caused complete inhibition of AChE activity after 30 min incubation at room temperature with either platelet-rich plasma or gel-filtered platelets. Complete inhibition of platelet AChE had no effect on platelet aggregation, factor-3 availability, and plasma clot retraction. We conclude that platelet membrane AChE activity is not required for normal platelet function as measured by these in vitro parameters.

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