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 mix ture.When methanol was added to the reaction mixture , fatty acid methyl esters were ob tained 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 lipolytic acyl-hydrolase was purified about 220-fold from the homogenate of the leaves of Phaseolus vulgaris L. cv. Kurodane-kinugasa by acetone precipitation, affinity chromato graphy on a palmitoylated gauze column and isoelectric focusing. The purified enzyme showed a single protein band by polyacrylamide gel disc electrophoresis. The enzyme had an isoelectric point of 4.4 and a molecular weight of about 90,000. It had pH optima of 5.5 and 6.5, and Km values of 0.24 and 0.53 mm for monogalactosyldiacylglycerol and phos phatidylcholine, respectively. The pH dependences were changed by Triton X-100. No separation of these two hydrolyzing activities were achieved, and the ratio of the specific activity of galactolipase to that of phospholipase (about 3/1) remained constant throughout the purification procedures. Both the activities changed in parallel with each other by the addition of reagents and by heat treatment. The enzyme clearly catalyzed the deacylation of the several classes of glyco-and phospholipids. These results suggest that a single enzyme is responsible for both the activities.
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