Occurrence of phospholipase A1–A2 and lysophosphatidylcholine acyltransferase activities in axolemma‐enriched fractions of brain stem, optic pathway, and cranio‐spinal nerves of the rabbit

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Abstract
An axolemma‐enriched fraction was isolated and characterized from homogenates of brain stem, pooled optic nerve and tract, and sciatic and hypoglossal nerves of adult rabbits. In these fractions, the phospholipase A1 and A2, as well as the activity of acylCoA:2 ‐ acyl ‐ sn ‐ glycero ‐ 3 ‐ phosphorylcholine acetyl transferase, using 1‐acyl‐ and 2‐acyl‐GPC as acyl acceptors, were studied. The activity of the four enzymes was clearly detecable in the central nervous system (CNS) and peripheral nervous system (PNS) axolemmatic perparations, as well as in other subcellular fractions examined. The axolemma fracions, in which acetylcholinesterase displayed the highest activities, were particularlyenriched in the acylatin reaction enzymes. These latter showed specific activities about twofold higher compared with those of the homogenates and significant correlation with acetylcholinesterase. The noticeable presence of these enzymeactivities in both CNS and PNS axolemma suggests that a deacylation–reacylation system for phospholipids may be operative in this membrane.