Positional Specificity of Phosphatide Acyl Hydrolase (Phospholipase A)

Abstract

SNAKE venom phospholipase A was shown by de Haas and van Deenen to release the fatty acid constituent present in the β-ester position of mixed-acid phospholipids obtained by a synthesis de novo^1–3. This result confirmed those of Tattrie⁴ and Hanahan et al.⁵, who worked on fatty acid distribution in egg lecithin, using phospholipase A, phospholipase D and pancreatic lipase. Hence, the positional specificity of phospholipase A appeared to be settled. Recently Bennett and Tattrie⁶, however, reported, because of reacylation investigations of snake-venom-formed lysolecithin, that this enzyme may not invariably hydrolyse the β-fatty acid ester bonds. This assumption supports the interpretation previously made by Marinetti et al.⁷, indicating a preference of the enzyme for liberating long-chain poly-unsaturated fatty acids, irrespective of their position in the phospholipid molecule. For this reason further investigations into the mode of action of phospholipase A were made.