In Vitro Fatty Acid Synthesis and Complex Lipid Metabolism in the Cyanobacterium, Anabaena Variabilis: II. Acyl Transfer and Complex Lipid Formation

Abstract

In vitro fatty acid transfer to form complex lipids was observed in crude cell extracts of Anabaena variabilis using [1-(14)C]palmitoyl-acyl carrier protein, [1-(14)C]stearoyl-acyl carrier protein, and [1-(14)C]oleoyl-acyl carrier protein substrates. The data indicated that there was a rapid transfer of the fatty acids into the complex lipids. The greatest amount of radioactivity was observed in the monogalactosyl diacylglycerol fractions and there appeared to be a preference for the transfer of stearate over palmitate. The exogenously added lysophospholipids, (lysophosphatidylglycerol, lysophosphatidylcholine) and 2-monopalmitin acted as acceptors in acyl transfer. Addition of the hypolipidemic drug, WY14643, inhibited the fast acyl transfer reaction and showed that the first product of acyl transfer was diglyceride followed by monogalactosyl diacylglycerol. Thioesters of Coenzyme A do not seem to be involved in these reactions.