Partial purification and characterization of antimicrobial peptide from the hemolymph of cockroach Periplaneta americana

ABSTRACT

The partial purification and characterization of antimicrobial peptide (AMP) from the hemolymph ofcockroach, Periplaneta americana, was studied. Hemolymph was drawn from cockroach and the AMP waspurified on a sephadex G-75 gel filtration column. The gel filtration showed two peaks, I and II, and only peakII showed five active fractions, namely, 12, 13, 14, 15, and 16, of antimicrobial activity. Fraction 13 showedthe highest microbial Inhibition concentration (MIC) and a single protein band on SDS-PAGE(sodium dodecylsulfate–polyacrylamide gel electrophoresis) with a molecular mass of 60.2 kDa. Purified antimicrobial proteinexhibited the highest antimicrobial activity against Escherichia coli at 30°C, pH 6.0, and 5 mM calcium ion.The AMP showed higher activity of MIC against lipopolysaccharides and β-1,3 glucan during 5 hours ofexposure. The study concludes that the AMP from hemolymph was effective against microbes or was able torecognize the molecular pattern of microorganisms