Identification of vasopressor phospholipid in crude soybean lecithin

The vasopressor phospholipid in crude soybean lecithin was isolated by column chromatography on Sephadex LH‐20. It represented 0.1% of crude soybean lecithin. The isolated phospholipid was identified to be lysophosphatidic acid by gas chromatography‐mass spectrometry analysis of TMS‐deacylated product and acetolysis product. Nuclear magnetic resonance analysis favored the 1‐monoacyl isomer over the 2‐isomer. By enzymic determination with L‐3‐glycerophosphate dehydrogenase, the isolated phospholipid was identified as 1‐monoacyl‐L‐3‐glycerophosphate. Gas chromatographic examination revealed that it was composed of a large percentage of unsaturated fatty acids, especially linoleic acid. The activity of isolated lysophosphatidic acid was slightly less than that of synthetic 1‐linoleoyl‐L‐3‐glycerophosphate.