Isolation and biological properties of scorpionvenom proteins: iv-comparative study on four proteinases isolated from the venom of isometrus vittatus

Abstract

1) Four proteinases were isolated from the venom of a local scorpion species Isonietrus vittatus collected from Sindh region, Pakistan and named PRO,(IA) PRO,(IB) PRO(IVA) and PRO(IVB). 2) Successive chromatography on Sephadex G-50, CM-Cellulose and Sephadex G-100 yield 25.5 mg, 20.5 mg, 24.0 mg and 20.0 mg of PRO,(IA) PRO(IB), PRO,(IVA) and PRO(IVB) respectively. 3) The purified toxins were homogenous by gel filtration chromatography and SDS-polyacrylamide gel electrophoresis (SDS-PAGE) giving single peak and band with an apparent molecular weight of 80.0 kda, 75.5 kda, 19.0 kda and 17.0 kda by gel filtration and 81.0 kda, 74.7 kda, 18.25 kda and 17.2 kda by SDS-PAGE. 4) PRO,(IA) PRO,(IVA) and PRO(IVB) have LD(50s) of 1.27 mg/kg, 1.91 mg/kg, 1.68 and 1.70 mg/kg respectively. The former two also caused marked alteration of serum enzyme and chemical constituent levels at sublethal dose whereas PRO(IVA) and PRO(IVB) were found to be less effective. 5) Enzymatic and biological activities of all four were inhibited by heating at 62 degrees C. Both activities were also inhibited by 1.8 mM EDTA and 1.2mM PMSF. Activities were enhanced by Ca(2+) but retarded and inhibited by Cu(4+) and Mg(2+), respectively.