Biochemical characterization of buffalo (Bubalus bubalis) milk lysozyme.

Lysozyme, a low-molecular weight basic protein, is an important component of the antibacterial system in milk. Lysozyme activity is higher in buffalo milk (60±3.9r 10 units/ml) than in bovine milk (29.1±1.5r10 units/ ml). Buffalo colostrum contains five-times more lysozyme activity than mature milk (Priyadarshini & Kansal, 2002a). Lysozyme activity in buffalo milk is not influenced by the parity of animal or stage of lactation, but it increases during extreme weather (winter and summer). Lysozyme in buffalo milk is more stable than in cow milk during storage and heat treatment. A sharp increase in milk lysozyme has been observed in buffaloes with sub-clinical mastitis (Priyadarshini & Kansal, 2002a). The molecular weight of buffalo milk lysozyme is 16 kDa as determined by sodium dodecyl sulphatepolyacrylamide gel electrophoresis (SDS-PAGE). The sequence of 23 amino acid residues at the N-terminal end shows 56.5% homology with bovine milk lysozyme and 30.4% with equine milk lysozyme. The specific activity of buffalo milk lysozyme is 10-times that of bovine milk lysozyme. Buffalo milk lysozyme is active over a wide range of pH and its activity is strongly influenced by the molarity of the medium (Priyadarshini & Kansal, 2002b). The anti-bacterial activity of buffalo milk lysozyme against Micrococcus luteus, Bacillus subtilis, Enterococcus faecalis and Lactococcus lactis ssp. lactis has been demonstrated (Priyadarshini & Kansal, 2002b). In this paper we report further biochemical characterization of buffalo milk lysozyme.