PHOSPHATIDYLCHOLINE MOLECULAR-SPECIES FORMED BY LYSOPHOSPHATIDYLCHOLINE ACYLTRANSFERASE FROM SOYA BEAN MICROSOMES

Lysophosphatidylcholine acyltransferase (LPC-AT) activity was measured in soya bean microsomes with [1-C-14]oleoyl-CoA as a substrate and in the presence of only microsomal endogenous lysophosphatidyicholine. Five phosphatidylcholine molecular species have been found labelled under these conditions and 95% of the [C-14]oleoyl residues were located at position 2 of sn-glycerol. When exogenous labelled lysophosphatidylcholines (either 1-acyl or 2-acyl lysophosphatidyl [C-14]choline) were supplied to the microsomes in the presence of unlabelled oleoyl-CoA, the esterification of the oleoyl residue occurred at position 1 as well as at position 2 of sn-glycerol. These results argue for a non-selective acylation of lysoPC substrates by microsomal LPC-AT.