SUBSTRATE-SPECIFICITY OF THE LIPASE FROM CANDIDA-PARAPSILOSIS

Substrate specificity of the acyltransferase activity of the lipase (E C 3.1.1.3) from Candida parapsilosis CBS 604 was studied in aqueous me dia, The specificity toward both acid and alcohol parts of a large num ber of acylglycerols and aliphatic esters was investigated. This lipas e showed a high activity in the presence of esters with long-chain fat ty acids and particularly unsaturated fatty acids with a cis-Delta 9 d ouble bond. It was observed that the activity profile depended not onl y on the alcohol part of the acyl ester, but also on the temperature o f the reactant medium. The best lipid substrates had their melting poi nt between -40 to +20 degrees C, 14 to 18 carbon atoms in the acyl gro up and 1 to 4 carbon atoms in the alkyl group. The enzyme, defined as an acyltransferase in a previous paper, showed a high affinity for pri mary and secondary alcohols with a short carbon chain (1 to 5 carbon a toms) as acyl accepters. The influence of free alcohols in the reactan t medium on the hydrolysis and alcoholysis activities of the enzyme is discussed. Two phenomena seem to be involved, depending on the alcoho l: competition with water for the acyltransfer reaction and lipid subs trate dilution when the alcohol places at the oil/water interface.