1-Acyl-2-lysophosphatidylcholine: phosphatidylglycerol-2-acyltransacylase in lung microsomes and type II pneumocyte-derived cultures.

The formation of [3H]phosphatidylcholine from 1-acyl-2-lysophosphatidylcholine and 1-acyl-2-[9,10-3H]palmitoylphosphatidylglycerol, presumably by 1-acyl-2-lysophosphatidylcholine : phosphatidylglycerol-2-acyltransacylase (phosphatidylglycerol transacylase), was detected in lung microsomes and Set 4 type II pneumocyte-derived cultured cells but not in A549 adenocarcinoma-derived type II cell analogs. There was greater phosphatidylglycerol transacylase activity in Set 4 cells at confluence than at the mid-log stage. Since the phosphatidylglycerol transacylase activity was always markedly less than that observed for 1-acyl-2-lysophosphatidylcholine : acyl-CoA acyltransferase, the former does not appear to represent a major pathway for synthesis of pulmonary dipalmitoylphosphatidylcholine.