The effects of serum amyloid P component (SAP) and heparin on the thrombin-catalyzed
formation of polymeric fibrin from purified fibrinogen were examined using a turbidometric
method to quantify fibrin polymerization. SAP and heparin acted synergistically to
inhibit the lateral aggregation of fibrin fibrils, resulting in the formation of fibrils
with a smaller mass to length ratio. Heparin did not enhance the incorporation of
SAP into fibrin clots, and the effect of heparin and SAP did not seem to be related
to inhibition of thrombin or of fibrinopeptide release. The evidence suggests that
a soluble complex of SAP and heparin inhibits fibrin polymerization.
Keywords
Amyloid P component - Heparin - Fibrin polymerization