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Enzymatic hydrolysis of 1‐monoacyl‐SN‐glycerol‐3‐phosphorylcholine (1‐lysolecithin) by phospholipases from peanut seeds
Author(s) -
Strauss H.,
Gershon Z. LeibovitzBen,
Heller M.
Publication year - 1976
Publication title -
lipids
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.601
H-Index - 120
eISSN - 1558-9307
pISSN - 0024-4201
DOI - 10.1007/bf02532834
Subject(s) - chemistry , hydrolysis , phosphatidylcholine , lysophospholipase , lecithin , lysophosphatidylcholine , chromatography , substrate (aquarium) , phospholipase a1 , phospholipase , enzyme , phospholipid , enzymatic hydrolysis , biochemistry , membrane , biology , ecology
Abstract Hydrolysis of 1‐lysolecithin (1‐acyl glycerophosphorylcholine [1‐acyl GPC]) by preparations of phospholipase D from peanut seeds was investigated. 1‐Lysolecithin was hydrolyzed at a much slower rate than phosphatidylcholine (lecithin). Although Ca +2 ions are required for the cleavage of lecithin by the enzyme, their effect on the hydrolysis of lysolecithin depended upon the concentrations of the substrate: at 0.2 mM 1‐lysolecithin, Ca +2 ions increased the reaction rates, whereas at concentrations of the substrate lower than 0.1 mM, Ca +2 ions were inhibitory. A broad pH activity curve between 5 and 8 was obtained with higher rates in the alkaline range, both in the absence and presence of Ca +2 ions. The increased hydrolysis of lysolecithin due to Ca +2 was noticed over the entire pH range. Upon storage of the enzyme solutions at 4 C, decreased rates of hydrolysis of lecithin were observed, with t 1/2 values of ca. 50 and 100 days depending on the purity of the preparation. During the same period, no reduction occurred in the activity of these preparations on lysolecithin as substrate. The effects of Ca +2 ions and the analysis of the products of 1‐acyl GPC cleavage by the enzyme preparations revealed by the enzyme preparations revealed the presence of more than one enzyme and the formation of the following compounds: lysophosphatidic acids (1 acyl glycerophosphoric acids), free fatty acids, glycerophosphorylcholine, and choline. The possible pathways leading to the degradation of lysolecithin and the formation of these products include reactions catalyzed by lysophospholipase A 1 (lysophosphatidylcholine 1‐acyl hydrolase, E.C. 3.1.1.5) and a phosphodiesterase (L‐3‐glycerylphosphorylcholine glycerophosphohydrolase, E.C. 3.1.4.2), in addition to phospholipase D (phosphatidylcholine phosphatidohydrolase, E.C. 3.1.4.4).