Summary
Degradation products of fibrinogen and fibrin resulting from the hydrolytic action
of plasmin, trypsin, chymotrypsin and papain were prepared and the two major polypeptide
fragments were found to have inhibitory effects on the coagulation mechanism including
inhibition of thromboplastin generation and inhibition of the conversion of the fibrinogen
to fibrin. The inhibitory actions of each of the isolated components were characterized
specifically for their role in each of these coagulation functions.
Both the slow (D) and fast (E) fragments of fibrinogen and fibrin hydrolysis by plasmin
degradation showed equally inhibitory effects against fibrinogen to fibrin conversion
by thrombin and fibrin monomer polymerization. The slow component of both was more
inhibitory. Both fast and slow digestion products of tryptic hydrolysis inhibited
thromboplastin generation and fibrinogen to fibrin conversion and fibrin monomer polymerization
equally. The fast component of chymotrypsin hydrolysis showed greater inhibition against
thromboplastin generation and fibrin monomer polymerization, than did the slow component.
Only a slow moving (D) component was obtained with papain digestion. It had no inhibitory
function against thromboplastin generation and only minimal effect against fibrin
monomer polymerization. The mechanism of inhibition of the thromboplastin generation
test by fibrinogen degradation products is a neutralization or inhibition of factor
IX.