Hydrolysis of glycerides by organic-solvent-soluble lipase

To investigate the structural properties of the active site in the lipase molecule, several glycerides have been hydrolysed by organic-solvent-soluble lipase in a homogeneous solvent system consisting of a buffer and tetrahydrofuran (1:4, v/v). 2-Monoacyl glyceride was not digested by this enzyme. For other glycerides, varying the acylated position in glycerol affects the Michaelis constant for interaction with the organic-solvent-soluble lipase, although the maximum velocity value between each glyceride and the organic-solvent-soluble lipase is similar. The values of Km for 1-monopalmitim, 1,2-dipalmitin, 1,3-dipalmitin and tripalmitin are 19.35, 11.69, 5.85 and 5.34 mmol dm–3, respectively. The effect of both the length and number of unsaturated bonds in the fatty acid chain in the glyceride has been investigated in detail. The results suggest that the three-dimensional structure of the fatty acid side chains of the glycerides does not affect the hydrolysis reaction and that the affinity of glycerides towards the enzyme depends on the conformation of the glycerol moeity.