Physalaemin- and Bombesin-like Peptides in the Skin of the Australian Leptodactylid Frog Uperoleia rugosa

Biologically active peptides of the tachykinin and bombesin families occurring in the skin of the Australian leptodectylid frog Uperoleia rugosa were isolated in pure forms and their structures were determined. Uperolein-like peptide 1 was identified, as expected, as authentic uperolein; uperolein-like peptide 2 was found to have the sequence Pyr-Ala-Asp-Pro-Lys-Thr-Phe-Tyr-Gly-Leu-Met-NH and may be considered a Lys, Thr-physalaemin. Bombesin-like peptide 1, in its turn, was identified as Glu(OEt)-litorin, and bombesin-like peptide 2 as authentic litorin. Uperolein and litorin had previously been identified in Uperoleia rugosa and Litoria aurea, respectively; the other two peptides are new. Glu(OEt)-litorin and Lys. Thr-physalaemin appear to have biological activities very similar to those of Glu(OMe)-litorin and physalaemin (or uperolein), respectively