Further Properties of a Lipolytic Acyl-hydrolase from Phaseolus Vulgaris Leaves

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A lipolytic acyl-hydrolase purified from Phaseolus vulgaris catalyzed the hydrolysis of fatty acid ester bonds at both C-1 and C-2 positions of the glycerol of monogalactolipid and phosphatidylcholine, and the corresponding lysolipids were not detected in the reaction mixture. When methanol was added to the reaction mixture, fatty acid methyl esters were obtained in the products. These results suggest that the enzyme not only has activity to completely deacylate both galacto- and phospholipids but also has acyl transferase activity.
A competitive relation was found between monogalactosyldiacylglycerol and phosphatidylcholine as substrates of the enzyme, indicating that the active sites toward both substrates are the same.
The chemical modification suggested that histidine and tryptophan residues are important to the enzymic activities.