Isolation and characterization of cationic antibacterial proteins and peptides from goat tongue epithelium

Natural endogenous peptide antibiotics constituted innate immunity associated with epithelial cells and phagocytes in hostile environment. In view of paucity of information on antibacterial proteins and peptides of goat tongue epithelium, the present study has been undertaken. The goat tongue epithelial acid extract subjected to Sephadex G-50 gel permeation chromatography revealed presence of 3 peaks and Sephacryl S-100 HR gel permeation resolved into four peaks. In AU-PAGE, the majority of cationic proteins corresponded to the reference lysozyme. The SDS-PAGE based molecular weight determination of cationic proteins and peptides was in the range of 11 to 66 KDa in 15% gel. The cationic peptide bands were detected below 20 KDa marker range in 10-35% SDS-PAGE with increased buffer concentration. The absorbance maxima of these peptides was at 240 nm and lacked gelatinase activity. Peak III fraction separated using Sephadex G-50 column as well as lower than 5 KDa fractions isolated using Centrisart membrane filters were found to contain antibacterial activity against Escherichia coli and Stophylococcus aureus.