Peptides from Australian frogs. Structures of the caerins and caeridin 1 from Litoria splendida

Abstract

Seven peptides have been isolated from the parotoid and rostral glands of the Australian green tree frog Litoria splendida. These include caerulein (a known hypotensive toxin), and six new compounds named caerin 1.1 (M, 2582), 1.1.1 (2412), 1.1.2 (2299), 2.1 (2392), 3.1 (2382) and caeridin 1 (1139). The primary structures of the peptides have been determined by FAB mass spectrometric methods, and confirmed by automated sequencing. The major peptides have been synthesised using t-BOC (N-tert-butoxycarbonyl)N-protection and a p-methylbenzhydrylamine support.