and sequential chromatography on first anion-exchange-, hydrophobic- and second anion-exchange columns followed by gel filtration and anion-exchange HPLC. The final enzyme preparation showed a single band with an apparent molecular mass of approx. 64 kDa by sodium dodecyl sulfate-polyacrylamid e gel electrophoresis. The purified enzyme had a pH optimum in the range of pH 7.0-9.0. Using ρ-nitrophenyl myristate or triolein as a substrate, the enzyme required the presence of sodium taurocholate or sodium cholate for its activity. No activity was observed in the presence of sodium deoxycholate. The enzyme preferentially hydrolyzed ethyl esters of polyunsaturated fatty acid, such as arachidonic acid and eicosapentaenoic acid which were resistant to porcine pancreatic lipase. These results strongly suggest that the enzyme purified from the hepatopancreas of red sea bream is homologous to mammalian bile salt-activated lipase.