Abstract

<jats:p>The dorsal glandular extract of the toadlet Uperoleia mjobergii contains more than 20 peptides. We report the amino acid sequences of the seven major peptides: these were determined by a combination of mass spectrometry and automated Edman sequencing. Three of these peptides have 19 amino acid residues and belong to the uperin 2 group of peptides [e.g. uperin 2.6, Gly Ile Leu Asp Ile Ala Lys Lys Leu Val Gly Gly Ile Arg Asn Val Leu Gly Ile (OH)], while the other four have 17 residues and are classified as uperins 3 [e.g. Uperin 3.4, Gly Val Gly Asp Leu Ile Arg Lys Ala Val Ala Ala Ile Lys Asn Ile Val (NH2)]. Several of these cationic peptides have been synthesized in order for bioassays to be carried out: they show significant antibiotic activity against a range of Gram-positive microorganisms. A major skin peptide from the related species Uperoleia inundata is a powerful neuropeptide named uperin 1.1 ([Ala2] uperolein ): no corresponding neuropeptide is detected in the skin glands of Uperoleia mjobergii.</jats:p>