Peptides from the Skin Glands of the Australian Buzzing Tree Frog Litoria electrica. Comparison with the Skin Peptides of the Red Tree Frog Litoria rubella

Abstract

Eleven peptides have been isolated from the skin glands of the ‘buzzing tree frog’ Litoria electrica. The two most abundant peptides are tryptophyllin L 3.1 [Phe Pro Trp Pro (NH₂)] and electrin 1 [Phe Val Pro Ile Tyr Met (NH₂)]. These peptides show neither significant antimicrobial nor smooth muscle activity. Tryptophyllin L 3.1 is thought to be a neuromodulator or neurotransmitter, and it is similar in structure to the human endomorphins [e.g. Tyr Pro Trp Phe (NH₂)] which act on the γ-receptor. Both Litoria electrica and the ‘red tree frog’ Litoria rubella produce tryptophyllin peptides: it is considered that both species evolved from the same ancestor.