Purification and partial characterization of a thrombin-like/gyroxin enzyme from bushmaster (Lachesis muta rhombeata) venom.

The acidic coagulating enzyme of the L. m. rhombeata venom was purified to homogeneity using one step on preparative isoelectric focusing followed by gel permeation on a high performance liquid chromatography system. The enzyme focused with pIs 3.1-5.0 and had a molecular mass of 47,000 mol. wt as determined by high performance liquid gel-filtration chromatography and about 45,000 mol. wt as judged by sodium dodecyl sulfate-polyacrylamide-gel electrophoresis. The enzyme is a glycoprotein containing sialic acid and 12.4% of neutral carbohydrates. The 30 N-terminal amino acid sequence of the L. m. rhombeata protein shows 100% identity with L. m. muta gyroxin and considerable sequence homology with gyroxin and thrombin-related proteins. The enzyme exhibits strong N-p-tosyl-L-arginine methyl esterase activity, hydrolyses tripeptide nitroanilide derivatives weakly or not at all, and cleaves specifically the fibropeptide A (alpha-chain).