PURIFICATION, CHARACTERIZATION AND CONFORMATIONAL-ANALYSIS OF A HAEMORRHAGIN FROM THE VENOM OF AGKISTRODON ACUTUS

AaHIV, a medium-sized toxin with a mol. wt of 44,000, a pI of 5.0 and a low cysteine content, was isolated from the venom of Agkistrodon acu tus by ion-exchange and gel filtration chromatography. It had haemorrh agic, lethal and caseinolytic activities, the last of which was inhibi ted by EDTA, Zn(CH2COO)(2) or CuSO4. The circular dichroism spectrum a t pH 7.0 showed two negative bands at 210 nm and 219 nm, corresponding to secondary structure contents of 18.2% alpha-helix, 31.0% beta-shee t, 17.2% beta-turn and 33.6% random-coil. The effect of various pH val ues or the addition of EDTA or Zn(CH3COO)(2) on the circular dichroism spectrum was also investigated. (C) 1997 Elsevier Science Ltd.