Objective\ To purify
blood coagulation factor Ⅹ activator from the venom of Vipera russelli
siamensis and investigate some
of its properties.\ Methods\ Ⅹ activator was purified from the venom of Vipera russelli siamensis by ion\|exchange chromatography and gel filtration.\ Its activity was measured by plasma clotting and chromogenic substrate(S\|2222).\ Temperature, pH and proteinase inhibitors used for detecting the effect of activity.\ The molecular weight, and isoelectric point were measured on SDS\|PAGE.\ The content of sugar was determined by phenol\|sulfuric acid and resorcinol hydrochloric acid methods.\ Results\ The extraction of procoagulating component Ⅳ\-1 may specially activate bovine factor Ⅹ and hydrolyze the amide bond of factor Ⅹa substrate S\|2222.\ VRS\|Ⅹ migrated as a single protein band in SDS\|PAGE.\ The molcular wight was estimated to be 61 1±1 5 kD in reducing conditions and 60 4±1 9 kD in non\|reducing conditions.\ It is a glucoprotein containing 12 4%±0 5% neutral hexose and 0 12%±0 02% sialic acid.\ It was quite stable under 50 ℃, the optimum pH was 7 0~8 2.\ The procoagulant activity of VRS\|Ⅹ was almost completely
inhibited by metal chelator EDTA\|Na\-2 and partially inhibited by L\|cysteine and DTT, but not inhibited by trypsin inhibitor(aprotinin).\ Conclusion\ FⅩ activator from the venom of Vipera russelli siamensis is a glucoprotein , which belong to Ca\+\{2+\} dependent metal protease.\;