Amino acid sequence of a thrombin like enzyme, elegaxobin, from the venom of Trimeresurus elegans (Sakishima-habu)

Abstract

The amino acid sequence of a thrombin like enzyme, named elegaxobin, isolated from the venom of Trimeresurus elegans (Sakishima-habu) was determined by Edman sequencing of the peptides, derived from digests with cyanogen bromide, hydroxylamine, achromobacter protease I, trypsin, V8 protease, and chymotrypsin. Elegaxobin showed conservation of the catalytic amino acid residues (His, Asp, and Ser) of trypsin like serine protease in the amino acid sequence. The carboxy-terminal amino acid, Leu, was determined using carboxypeptidase Y. Elegaxobin consisted of 233 amino acids and had a calculated molecular weight of 25,439. Elegaxobin was 53, 59, 26 and 40% homologous in sequence to ancrod, flavoxobin, bovine thrombin and trypsin, respectively.