Catabolism of N-Acylethanolamine Phospholipids by Dog Brain Preparations |
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Authors: | V Natarajan P C Schmid P V Reddy H H O Schmid |
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Institution: | The Hormel Institute, University of Minnesota, Austin, Minnesota, U.S.A. |
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Abstract: | Abstract: N -Acylphosphatidylethanolamine, incubated with dog brain homogenate or microsomes, was hydroyzed to phosphatidic acid and N -acylethanolamine by a phosphodiesterase of the phospholipase D type. In the absence of F−, phosphatidic acid was further hydrolyzed to diacylglycerol and Pi while N -acylethanolamine was hydrolyzed by an amidase to fatty acid and ethanolamine. The phosphodiesterase showed an alkaline pH optimum and was also active towards N -acetylphosphatidyletha-nolamine, N -acyl-lysophosphatidylethanolamine, and glycerophospho( N -acyl)ethanolamine but showed little activity toward phosphatidylethanolamine and phosphati-dylcholine. Ca2+ stimulated slightly at low concentrations but inhibited at higher concentrations. Triton X-100 stim ulated the hydrolysis of N -acylphosphatidylethanol-amine, inhibited that of N -acyl-lysophosphatidyletha-nolamine and glycerophospho( N -acyl)ethanolamine, and had no effect on phosphatidylethanolamine or phospha-tidylcholine hydrolysis. The N -acylethanolamine hydrolase (amidase) was also present in the microsomal fraction and exhibited a pH optimum of 10.0. In addition to hydrolysis by the phosphodiesterase, N -acylphosphati-dylethanolamine was also catabolized by microsomal phospholipases A1 and/or A2 to N -acyl-lysophosphati-dylethanolamine, some of which was further hydrolyzed to glycerophospho( N -acyl)ethanolamine. |
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Keywords: | Dog brain N-Acylethanolamine phospholipids Phospholipase D N-Acylethanolamine amidase |
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