Two N-terminally truncated forms of C-type natriuretic peptide from habu snake venom

Two N-terminally truncated forms of the C-type natriuretic peptide (CNP) were isolated from the venom of habu snake, Trimeresurus flavoviridis, and their structures were determined by EMI-MS spectrometry and amino acid sequencing. Tf-CNP(6-22), the shorter peptide retaining the 17-membered ring structure formed by an intra-molecular disulfide bridge, has a vasorelaxant activity in rat aortic strips and a diuretic potency in anesthetized rats. Tf-CNP(3-22), the other 20 amino acid residues peptide, also comprised the 17- membered ring with a short N-terminal extension of 3 amino acid residues. Tf-CNP(6-22), the ring, is the shortest naturally occurring CNP peptide identified so far, and as potent as Tf-CNP(1-22), the supposedly intact CNP of 22 amino acid residues.