Differences between binding of one-chain and two-chain tissue plasminogen activators to non-cross-linked and cross-linked fibrin clots

Journal Article · Tue Aug 15 04:00:00 EDT 1989 · Blood; (USA)

OSTI ID:5673570

Husain, S S; Hasan, A A; Budzynski, A Z ^[1]

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1. Temple Univ. School of Medicine, Philadelphia, PA (USA)

Interaction of tissue plasminogen activator (t-PA) with fibrin plays a key role in regulation of plasminogen activation and clot dissolution. Previous investigations of t-PA-fibrin interaction, using incorporation of t-PA into polymerizing fibrin clots, have suggested that no significant differences exist in the binding of one-chain or two-chain t-PA to non-cross-linked or cross-linked fibrin. In the present study, binding of 125I-labeled and affinity-purified one-chain and two-chain forms of t-PA to preformed non-cross-linked or cross-linked, sonicated suspension of fibrin was investigated. Interaction of one-chain t-PA with cross-linked fibrin involved a single type of binding site with dissociation constant (kd) of 0.58 mumol/L and a stoichiometry (n) of 1.5. Interaction of one-chain t-PA with non-cross-linked fibrin, however, involved two classes of binding sites with dissociation constants of 0.32 and 1.5 mumol/L and corresponding number of binding sites equal to 0.57 and 2.0, respectively. In contrast to the binding of one-chain t-PA to cross-linked fibrin by a limited number of sites, two-chain t-PA appeared to involve a considerably greater number of sites (minimum six) whose dissociation constant was 3.2 mumol/L. Interaction of two-chain t-PA with non-cross-linked fibrin also showed the presence of many binding sites (minimum seven) with approximate dissociation constant of 6.4 mumol/L, as well as a few (n = 0.012) high-affinity sites with a kd of 0.011 mumol/L epsilon-Aminocaproic acid did not completely reverse the binding of either one-chain t-PA or two-chain t-PA to fibrin. The present findings suggest that the fibrin-binding properties of t-PA undergo considerable changes on proteolytic conversion from one-chain to two-chain t-PA, catalyzed under physiologic conditions by plasmin.

• OSTI ID: 5673570
• Journal Information: Blood; (USA), Journal Name: Blood; (USA) Vol. 74:3; ISSN BLOOA; ISSN 0006-4971
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ANIMALS
BETA DECAY RADIOISOTOPES
BIOCHEMICAL REACTION KINETICS
BLOOD COAGULATION
CHEMICAL REACTIONS
CHROMATOGRAPHY
COAGULANTS
CROSS-LINKING
DAYS LIVING RADIOISOTOPES
DECOMPOSITION
DRUGS
ELECTRON CAPTURE RADIOISOTOPES
FIBRIN
FIBRINOLYTIC AGENTS
HEMATOLOGIC AGENTS
HEMOSTATICS
INTERMEDIATE MASS NUCLEI
IODINE 125
IODINE ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
KINETICS
MAMMALS
MAN
MEMBRANE PROTEINS
NUCLEI
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
PLASMINOGEN
POLYMERIZATION
PRIMATES
PROTEINS
PROTEOLYSIS
RADIOISOTOPES
REACTION KINETICS
RECEPTORS
SCLEROPROTEINS
SEPARATION PROCESSES
TRACER TECHNIQUES
VERTEBRATES