Purification and characterization of lysozyme from brackishwater clam Corbicula japonica

Lysozyme was purified from brackishwater clam Corbicula japonica by sequent ial procedures with ammonium sulfate fractionation, and CHITOPEARL. BASIC B L-01 affinity, Hydroxyapatite, S-Sepharose Fast Flow, and CM-TOYOPEARL 650S column chromatographies. The purified enzyme showed a single protein band on polyacrylamide gel elec trophoresis (PAGE), and its molecular weight was estimated to be 12,000 by SDS-PAGE. Optimum pH of the enzyme was 4.8 toward Micrococcus lysodeikticus cells. The optimum temperature was 70 degrees C. The enzyme was stable in the range of pH 3.0-6.8 and 20-90 degrees C, respectively. The specific act ivity of the enzyme toward M. lysodeikticus cells was 256-fold higher than that of hen egg white lysozyme. The N-terminal amino acid sequence and amino acid composition of the enzyme were not similar to those of hen egg white lysozyme, suggesting a genetica l difference of both enzymes.