HKABF, Hippocampus kuda antibacterial factor, is a putative antimicrobial peptide identified from the cDNA library of the brooding pouch of H. kuda Bleeker. The putative mature peptide, fused with a 6His-tag, an anionic peptide (SAPLNPDNID) and to an enterokinase cleavage site was expressed. in Pichia pastoris. The mature HKABF peptide, released by enterokinase cleavage, showed antimicrobial activity against Staphylococcus aureus and Staphylococcus saprophyticus at low concentrations (0.5-2.5 mu g/ml). The recombinant mature peptide was heat-stable and had low hemolytic activity. Circular dichroism (CD) spectroscopy data indicates its classification as a CS alpha beta-type antimicrobial peptide. This study serves as an impetus for the production and further research of this antimicrobial peptide. (C) 2008 Elsevier Ltd. All rights reserved.