Complete Amino Acid Sequence of Snake Venom Phospholipase A₂

Abstract

Phospholipase A₂ (phosphatide acyl-hydrolase, EC 3.1.1.4) catalyzes hydrolysis of fatty acyl ester at the β position of phospholipid. This enzyme is widely distributed in the venoms of snakes, bees, and scorpions as well as in animal tissues. Recently, a number of forms of phospholipase A₂ have been highly purified from various species of Elapidae (Braganca et al., 1969; Salach et al., 1971; Shiloah et al., 1973a,b; Wahlström, 1971; Sakhibov et al., 1970; Lo and Chang, 1971), Hydrophiidae (Tu et al., 1970), Viperidae (Salach et al., 1971; Shiloah et al., 1970), and Crotalidae (Wells and Hanahan, 1969;Wu and Tinker, 1969; Augustin and Elliott, 1970). We have also isolated two forms of phosphohpase A₂ found in the venom of Agkistrodon halys blomhoffii, Japanese trivial name “Mamushi” (Iwanaga and Kawauchi, 1958, 1959;Kawauchi etal., 1971a). Acidic phospholipase A₂, designated as A₂-II, consists of a single polypeptide chain with a molecular weight of about 13,700 (Kawauchi et al., 1971a). It contains N-terminal pyroglutamic acid, C-terminal cystine, and a total of 126 amino acid residues (Kawauchi et al., 1971b). Following these works, we reported the gross structure of A₂-II, in addition to the complete or partial amino acid sequences of CNBr-peptide fragments and tryptic peptides (Samejima et al., 1970). In this paper, we present the complete amino acid sequence of phospholipase A₂-II of A. halys blomhoffii venom. The sequence is complete except for assignment of a few amide groups.