Abstract
Blomhotin is a novel peptide (pGlu1-Gly2-Arg3-Pro4-Pro5-Gly6-Pro7-Pro8-Ile9-Pro10-Arg11) which has been isolated from the venom of Agkistrodon halys blomhoffii and exhibits contractile activity on rat stomach fundus. We carried out a structure-activity study of blomhotin and its related peptides, and the findings suggested that the N-terminal portion of blomhotin is mainly responsible for affinity for the blomhotin receptor, whereas the C-terminal portion of blomhotin, Pro-Ile-Pro-Arg, is responsible for complete activation of the blomhotin receptor in the rat stomach fundus. In particular, the amino acids at positions 9 and 11 of blomhotin appear to be essential for binding and intrinsic activity. Using knowledge gained from this structure-activity analysis, we have identified photoactive blomhotin analogues that have sufficient biological activity to probe the target molecule of blomhotin.
