Activation of human factor V by factor Xa and thrombin

Journal Article · Tue Feb 06 04:00:00 EST 1990 · Biochemistry; (USA)

DOI:https://doi.org/10.1021/bi00457a004· OSTI ID:6709483

Monkovic, D D; Tracy, P B ^[1]

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1. Univ. of Vermont, Burlington (USA)

The activation of human factor V by factor Xa and thrombin was studied by functional assessment of cofactor activity and sodium dodecyl sulfate-polycarylamide gel electrophoresis followed by either autoradiography of {sup 125}I-labeled factor V activation products or Western blot analyses of unlabeled factor V activation products. Cofactor activity was measured by the ability of the factor V/Va peptides to support the activation of prothrombin. The factor Xa catalyzed cleavage of factor V was observed to be time, phospholipid, and calcium ion dependent, yielding a cofactor with activity equal to that of thrombin-activated factor V (factor Va). The cleavage pattern differed markedly from the one observed in the bovine system. The factor Xa activated factor V subunits expressing cofactor activity were isolated and found to consist of peptides of M{sub r} 220,000 and 105,000. Although thrombin cleaved the M{sub r} 220,000 peptide to yield peptides previously shown to be products of thrombin activation, cofactor activity did not increase. N-Terminal sequence analysis confirmed that both factor Xa and thrombin cleave factor V at the same bond to generate the M{sub r} 220,000 peptide. The factor Xa dependent functional assessment of {sup 125}I-labeled factor V coupled with densitometric analyses of the cleavage products indicated that the cofactor activity of factor Xa activated factor V closely paralleled the appearance of the M{sub r} 220,000 peptide. The data indicate that factor Xa is as efficient an enzyme toward factor V as thrombin.

• OSTI ID: 6709483
• Journal Information: Biochemistry; (USA), Journal Name: Biochemistry; (USA) Vol. 29:5; ISSN 0006-2960; ISSN BICHA
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ALKALI METAL COMPOUNDS
AUTORADIOGRAPHY
BETA DECAY RADIOISOTOPES
BIOCHEMICAL REACTION KINETICS
BLOOD COAGULATION
BLOOD COAGULATION FACTORS
CHEMICAL ACTIVATION
COAGULANTS
DAYS LIVING RADIOISOTOPES
DRUGS
ELECTRON CAPTURE RADIOISOTOPES
ELECTROPHORESIS
ENZYMES
HALIDES
HALOGEN COMPOUNDS
HEMATOLOGIC AGENTS
HEMOSTATICS
HYDROLASES
INORGANIC PHOSPHORS
INTERMEDIATE MASS NUCLEI
IODIDES
IODINE 125
IODINE COMPOUNDS
IODINE ISOTOPES
ISOTOPES
KINETICS
NUCLEI
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
PEPTIDE HYDROLASES
PHOSPHORS
PROTEINS
PROTHROMBIN
RADIOISOTOPES
REACTION KINETICS
SERINE PROTEINASES
SODIUM COMPOUNDS
SODIUM IODIDES
THROMBIN