Last step in the cooperative pathway for galactolipid synthesis in spinach leaves: Formation of monogalactosyldiacylglycerol with C18 polyunsaturated acyl groups at both carbon atoms of the glycerol

In this paper, the formation of monogalactosyldiacylglycerol (MGDG) with C18 polyunsaturated acyl groups at both positions of the glycerol from phosphatidylcholine (PC) of liposomes was demonstrated by a three-step procedure: spinach chloroplasts were first incubated with liposomes of PC-containing polyunsaturated fatty acids at both positions of the glycerol in the presence of phospholipid transfer protein. Chloroplasts were then incubated with phospholipase C in order to form 1,2-diacylglycerol (1,2-DAG) from PC integrated in the chloroplast envelope. Finally, washed chloroplasts were incubated with UDP-gal and MGDG was formed by galactosylation of 1,2-DAG.