Fibrinopeptide-releasing enzymes in the venom from the southern copperhead snake (Agkistrodon contortrix contortrix).

Abstract Protein fractionation techniques utilizing the different properties of the sample (size, charge, sugar moiety) were employed to characterize the crude A. c. contortrix venom. Gel filtration chromatography resolved about six to eight peaks, high performance liquid ion exchange chromatography and chromatofocusing about 12–14 peaks exhibiting hydrolytic activity. Two fibrin clot-promoting enzymes—both releasing fibrinopeptides A and fibrinopeptides B , but with different fibrinopeptide A /fibrinopeptide B relative rates were observed. The two enzymes (or enzyme isoforms) were serine proteinases with essentially the same hydrolytic activity towards low molecular chromogenic substrate for thrombin. They were of approximately the same size (one peak of 68,000 relative mol.wt on gel filtration chromatography), had apparent isoelectric points of about 6.4 and 5.4, respectively, and were glycoproteins.