BIOCHEMICAL AND STRUCTURAL CHARACTERIZATION OF TRIACYLGLYCEROL LIPASEFROM PENICILLIUM-CYCLOPIUM

An extracellular lipase, active on water-insoluble triacylglycerols, h as been isolated from Penicillium cyclopium. The purified enzyme has a molecular mass of 29 kDa by gel filtration and SDS-polyacrylamide gel electrophoresis. It hydrolyzes emulsions of tributyrin, trioctanoin, and olive oil at the same rate as pancreatic lipase and shows very low activity against partial acylglycerols (monooctanoin and dioctanoin) and methyl esters. It is stable at 35 degrees C for 60 min and has max imal activity in a pH range of 8-10. Hydrolysis of triacylglycerols by P. cyclopium lipase is inhibited by detergents such as Triton X-100. Comparison of the sequence of the 20 first amino acid residues of P. c yclopium triacylglycerol lipase with other Penicillium lipases indicat es a high homology with previously characterized lipases produced by P . expansum and P. solitum which are enzymes of comparable size and sub strate specificity. Conversely, homology between P. cyclopium lipase a nd P. simplicissimum lipase, a nonspecific lipolytic enzyme, is low. P enicillium cyclopium triacylglycerol lipase shows no homology with P. camembertii lipase which is specific to monoacylglycerol and diacylgly cerol.