Lipase from Antarctic krill,with a molecular weight of 71.27 kDa,was purified with ammonium sulfate precipitation and a series of chromatographic separations over ion exchange (DEAE) and gel filtration columns (Sephacryl S-100),resulting in 5.2％ re- covery with a 22.4-fold purification ratio.The optimal pH and temperature for enzyme activity were 8.0 and 45℃,respectively.Puri- fied lipase had Km and Vmax values of 3.27 mmol L?1 and 2.4 U mg?1,respectively,using p-nitrophenyl laurate as the substrate.Li-pase activity was enhanced by adding Ca2+ and Mg2+ ions in the concentration ranges of 0–0.5 mmol L?1 and 0–0.3 mmol L?1,respec-tively,while the activity was inhibited by a further increase in these ion concentrations.Fe3+ and Cu2+ ions showed obvious inhibitory effects on enzyme activity,and the inhibition rates were 71.8％ and 53.3％ when the ion concentrations were 0.5 mmol L?1.