On the activity of brain phospholipase A2 towards specifically labelled glycerophospholipids during subacute sclerosing panencephalitis

1,2-Diacyl-sn-glycero-3-phosphorylcholine, -ethanolamine and -serine, specifically labelled with different fatty acids at either the 1- or 2-position, were prepared enzymatically using the acyltransferase system of rat liver microsomes. The substrates were subjected to hydrolysis by phospholipase A2 obtained from brain tissue of a normal and a case of subacute sclerosing panencephalitis (SSPE). In the pathological tissue and increase of approx. 50% in phospholipase A2 activity could be observed in comparison to that from the control brain for all investigated substrates. Experiments with phosphatidylethanolamines, specifically labelled with different fatty acids in the 2-position, revealed that the phospholipase A2 activity of the SSPE brain tissue was enhanced by about 50% when compared to the control brain regardless of the fatty acid constituent at the 2-position of the substrates.