Bioactive dahlein peptides from the skin secretions of the Australian aquatic frog Litoria dahlii: sequence determination by electrospray mass spectrometry

Eleven dahlein peptides are present in the skin secretion of the Australian aquatic frog Litoria dahlii. All peptides have been sequenced using a comb ination of electrospray mass spectrometry (ES-MS) and Lys-C digestion/MS, w ith each sequence confirmed by automated Edman sequencing. The 13-residue d ahlein 1 peptides (e.g. dahlein 1.1 GLFDIIKNIVSTL-NH2) exhibit weak wide-sp ectrum antimicrobial activity but no significant activity in the anticancer testing program of the National Cancer Institute (Washington). There are n o potent antimicrobial peptides present in the glandular secretion, but the dahleins 5 strongly inhibit the formation of NO by neuronal nitric oxide s ynthase (e.g. dahlein 5.1 GLLGSIGNAIGAFIANKLKP-OH). Copyright (C) 2001 John Wiley & Sons, Ltd.