Isolation of human blood coagulation α-factor Xa by soybean trypsin inhibitor-Sepharose chromatography and its active-site titration with fluorescein mono-p-guanidinobenzoate

A novel α2-p1asmin inhibitor (α2Pl), chemically and immunologically distinct from any known inhibitors, has recently been isolated and characterized from human plasma (Moroi and Aoki, J. Biol. Chem. 251: 5956, 1976). We have studied the effect of purified α2PI upon various proteases participating in human blood coagulation and kinin generation. At physiological concentrations, (50 μg/ml), α2PI inhibited the clot-promoting and prekal1 ikrein-activating activity of Hageman factor fragments (HFf, MW = 30,000), the amidolytic, kininogen-ase and clot-promoting activities of plasma kallikrein, and the clot-promoting activity of activated plasma thromboplastin antecedent (activated PTA, XIa). For example, activated PTA was inhibited to 50% and 12% of original activity after incubation with α2PI for 10 and 30 min at 37°c respectively. At higher concentrations (200 μg/ml), activatedStuart factor (Xa) was also inhibited. Heparin (1.5 units/ml) did not enhance the inhibitory function of α2PI against HFf, plasma kallikrein or activated PTA. These results suggest that α2PI is an inhibitor of broad specificity that may play an important role in regulation of blood coagulation, fibrinolysis and kinin generation.

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Structural basis for chemical inhibition of human blood coagulation factor Xa

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.95.12.6630 ◽

1998 ◽

Vol 95 (12) ◽

pp. 6630-6635 ◽

Cited By ~ 90

Author(s):

K. Kamata ◽

H. Kawamoto ◽

T. Honma ◽

T. Iwama ◽

S.-H. Kim

Keyword(s):

Blood Coagulation ◽

Human Blood ◽

Factor Xa ◽

Coagulation Factor ◽

Structural Basis ◽

Chemical Inhibition ◽

Human Blood Coagulation

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Inhibition of human blood coagulation factor Xa by .alpha.2-macroglobulin

Biochemistry ◽

10.1021/bi00392a053 ◽

1987 ◽

Vol 26 (18) ◽

pp. 5932-5937 ◽

Cited By ~ 25

Author(s):

Joost C. M. Meijers ◽

Pim N. M. Tijburg ◽

Bonno N. Bouma

Keyword(s):

Blood Coagulation ◽

Human Blood ◽

Factor Xa ◽

Coagulation Factor ◽

Human Blood Coagulation

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Active-site mapping of bovine and human blood coagulation serine proteases using synthetic peptide 4-nitroanilide and thio ester substrates

Biochemistry ◽

10.1021/bi00299a009 ◽

1984 ◽

Vol 23 (4) ◽

pp. 644-650 ◽

Cited By ~ 49

Author(s):

Kyujin Cho ◽

Takumi Tanaka ◽

Robert R. Cook ◽

Walter Kisiel ◽

Kazuo Fujikawa ◽

...

Keyword(s):

Blood Coagulation ◽

Human Blood ◽

Active Site ◽

Synthetic Peptide ◽

Serine Proteases ◽

Site Mapping ◽

Human Blood Coagulation

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Factor X Activation by washed human platelets

10.1055/s-0038-1665669 ◽

1979 ◽

Author(s):

E van Wijk ◽

L Kahlé ◽

J ten Cate

Keyword(s):

Human Factors ◽

Trypsin Inhibitor ◽

Calcium Ions ◽

Factor Xa ◽

Human Platelets ◽

Soybean Trypsin Inhibitor ◽

Thrombin Inhibitor ◽

Chromogenic Substrate ◽

Factor X ◽

Factor X Activation

In a system of washed human platelets, Ca2+and purified human factors X anc II, a sufficient amount of thrombin is generated in about 10 minutes to aggregate the platelets. This thrombin is formed through the activation of FX by the platelets. In a system with either FX or FII present, no aggregation occurs. In addition no aggregation is observed when hirudin, a specific thrombin inhibitor, or when soybean trypsin inhibitor, which inhibits factor Xa, are added to the mixture. The formation of factor Xa can be monitored indirectly through the generation of thrombin, in the presence of an excess of prothrombin, using a thrombin sensitive chromogenic substrate. When washed platelets are incubated with FX alone for 10 minutes, no aggregation occurs and after the addition of prothrombin aggregation starts within 6 minutes. These findings confirm that washed platelets possess a factor X activating property. The generation of FXa proceeds in the absence of added Ca2+, whereas in the presence of Ca2+factor Xa activity reaches a maximum in 3 minutes, whereafter the activity progressively decreases. This may be due to the binding of Xa to the platelets in the presence of calcium ions.

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