PRIMARY STRUCTURE OF A COAGULANT ENZYME, BILINEOBIN, FROM AGKISTRODONBILINEATUS VENOM

The amino acid sequence and disulfide bridge location of the coagulant enzyme, named bilineobin, isolated from the venom of Agkistrodon bili neatus was determined by Edman sequencing of the peptides derived from digests with cyanogen bromide, clostripain, Staphylococcus aureus V8 protease, trypsin, and chymotrypsin. This enzyme has a molecular weigh t of 57,000 Da by sodium dodecyl sulfate-polyacrylamide gel electropho resis; however, bilineobin consists of 235 amino acids and has a calcu lated molecular weight of 26,481, The enzyme contains fucose, GlcNAc, galactose, mannose and NeuAc and six N-linked glycosylation consensus sites. The carboxyterminal amino acid, proline, was determined using c arboxypeptidase Y. The six disulfide bonds of bilineobin link Cys(78) to Cys(234), Cys(120) to Cys(188), Cys(178) to Cys(203), Cys(7) to Cys (141), Cys(152) to Cys(167), and Cys(28) to Cys(44). The amino acid se quence similarity to flavoxobin (T. C. Shieh et al., 1988, J. Biochem (Tokyo) 103, 596-605) and batroxobin (N. Itoh ed al., 1987, J. Biol. C hem. 262, 3132-3135) was 67%, The deglycosylated enzyme more rapidly g enerated fibrinopeptide A than native bilineobin. (C) 1995 Academic Pr ess, Inc.