Diversity of the ß-Bungarotoxin Family

Abstract

AbstractWe had applied an h.p.l.c. method to make an effective resolution of the isotoxins (P3-P18) of s-bungarotoxin family in one batch of Formosan krait (Bungarus multicinctus) venom from commercial source. The functional characteristics of P4-5, P8-9, P11, P13 and P15-18 were compared. They showed a great difference in their ability to hydrolyze phospholipid and to cause neurotoxic effect. P11 had the phospholipase activity of 373 unit/mg of protein and its LD50 was 0.012 mg/g body weight of mice. P4 and P5 showed 18 and 34% of the phospholipase activity of P11, and the other isotoxins had the enzyme activity comparable to that of P11. The lethal potency based on the LD50 values was in the order P15-18>P11>P9>P8>P5>P4. The LD50 of P4 was about 150 or 1100 times as large as that of LD50 of P11 or P16. We applied also our h.p.l.c. method to examine the distribution of s-bungarotoxin in two batches of Formosan krait venom collected separately from south China and Taiwan. The h.p.l.c. pattern of the isoto...