Activity and subcellular distribution of phospholipase A1 from neuronal cell-enriched fractions of the rabbit cerebral cortex.
Glycerophosphatides, specifically labeled either in the 1 or in the 2 position, were used to measure the activity of neuronal phospholipase A1 and to investigate the subcellular distribution of the enzyme. The microsomes were found to possess the highest phospholipase activity, with a threefold increase as compared to the cell homogenate. A considerable enzymatic activity could still be observed in the plasma membranes isolated from the neuronal-enriched cell fraction. Microsomal phospholipase possessed the highest activity with phosphatidylcholine, whereas phosphatidylserine was cleaved at a much lower rate. The rate of release of labeled fatty acids from the substrates by the microsomal phospholipase decreased with increasing degree of unsaturation of the fatty acids at the 1 position. The presence of plasmalogens and of alkylacyl analogues in the incubation mixture caused an appreciable inhibition of the hydrolysis of the diacyl glycerophosphatides.
D000818:Animals; D002540:Cerebral Cortex / Q000201:enzymology*; D005227:Fatty Acids; D009474:Neurons / Q000201:enzymology*; D010740:Phospholipases / Q000378:metabolism*; D010741:Phospholipases A / Q000378:metabolism*; D054466:Phospholipases A1; D011817:Rabbits; D013347:Subcellular Fractions / Q000201:enzymology; D013379:Substrate Specificity
D005227:Fatty Acids; D010740:Phospholipases; D010741:Phospholipases A; D054466:Phospholipases A1