Activation of immobilized plasminogen by tissue activator. Multimolecular complex formation

Journal Article · Sun Aug 25 04:00:00 EDT 1985 · J. Biol. Chem.; (United States)

OSTI ID:6335813

Silverstein, R L; Nachman, R L; Leung, L L; Harpel, P C

Ternary complex formation of tissue plasminogen activator (TPA) and plasminogen (Plg) with thrombospondin (TSP) or histidine-rich glycoprotein (HRGP) has been demonstrated using an enzyme-linked immunosorbent assay, an affinity bead assay, and a rocket immunoelectrophoresis assay. The formation of these complexes was specific, concentration dependent, saturable, lysine binding site-dependent, and inhibitable by fluid phase plasminogen. Apparent Kd values were approximately 12-36 nM for the interaction of TPA with TSP-Plg complexes and 15-31 nM with HRGP-Plg complexes. At saturation the relative molar stoichiometry of Plg:TPA was 3:1 within the TSP-containing complexes and 1:1 within HRGP-containing complexes. The activation of Plg to plasmin by TPA on TSP- and HRGP-coated surfaces was studied using a synthetic fluorometric plasmin substrate (D-Val-Leu-Lys-7-amino-4-trifluoromethyl coumarin). Kinetic analysis demonstrated a marked increase in the affinity of TPA for plasminogen in the presence of surface-associated TSP or HRGP. Complex formation of locally released tissue plasminogen activator with Plg immobilized on TSP or HRGP surfaces may thus play an important role in effecting proteolytic events in nonfibrin-containing microenvironments.

• Research Organization: New York Hospital-Cornell Medical Center
• OSTI ID: 6335813
• Journal Information: J. Biol. Chem.; (United States), Journal Name: J. Biol. Chem.; (United States) Vol. 18; ISSN JBCHA
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
BIOASSAY
COUMARIN
DRUGS
ELECTROPHORESIS
ENZYME IMMUNOASSAY
ENZYMES
ESTERS
FIBRINOLYSIN
FIBRINOLYTIC AGENTS
HEMATOLOGIC AGENTS
HETEROCYCLIC COMPOUNDS
HYDROLASES
IMMOBILIZED ENZYMES
IODINE ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
KINETICS
LACTONES
ORGANIC COMPOUNDS
ORGANIC OXYGEN COMPOUNDS
PEPTIDE HYDROLASES
PLASMINOGEN
PYRANS
SERINE PROTEINASES
TRACER TECHNIQUES