Characterization of a Bioactive Protein with Antimicrobial Property from Loligo sp.

Loligo is a genus of squids. Due to their abundance and economic importance in the export market, squids have been studied for their biology and fishery characteristics. The aim of the current study was to investigate anti-microbial activity associated with proteins extracted from this organism. Whole body tissue was homogenized with protein extraction buffer and its antimicrobial activity was screened against Klebsiella pneumoniae, Bacillus cereus, Salmonella typhimurium, Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa and Vibrio cholerae by agar well diffusion method. The protein was concentrated by acetone precipitation. Purification was done in different steps employing cut off membrane filtration, thin layer chromatograph y (TLC) and Sephadex G-50 gel filtration column. The molecular weight of the protein was determined by SDS-PAGE. A 45 kDa protein was isolated and purified from Loligo with a total yield of 0.06% which showed bioactivity against V. cholerae. MALDI and MASCOT analysis showed that the 45 kDa protein had a similarity score of 40 with parvalbumin protein of Fundulus similis.