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A chitinase-producing bacterium, Serratia marcescens JM, was isolated from a seashore muds. A chitinase was purified by ammonium sulfate precipitation, affinity adsorption, hydroxylapatite and sephadex G-200 column chromatography. The chitinase obtained from Serratia marcescens JM was purified 42.2 folds with the overall yield of 7.1%. The purified chitinase showed a single band on sodium dodecyl sulfate polyacrylamide gel electrophoresis. The molecular weight of the enzyme was 59,000 and the apparent kinetic parameters Km and Vmax for the purified chitinase were 5.17 mg/mL and 39.8 unit/mL, respectively. The optimum pH and temperature of the purified chitinase were 7.0 and 50℃, respectively and the purified enzyme was stable on pH 7.0 up to 50℃. The enzyme were activated by Cu2+, Ca2+ and Mg2+ and inhibited by Hg2+ respectively. In addition, Cysteine increased the chitinase activity and EDTA, MIA, PCMB and SDS inhibited enzyme activities. Major cations, Mg2+, Ca2+, K+ and Na+ present in seawater slightly stimulated the chitinase activity.
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