Metabolism of molecular species of sulpholipid in barley leaves

Molecular species of sulpholipid (diacylsulphoquinovosylglycerol) were separated and analysed after incubation of developing barley (Hordeum vulgare) leaves with either (1-¹⁴C]-acetate or [³⁵S]-sulphate. The major endogenous molecular species were the trienoic (42%) and the hexaenoic (39%). However, the combined anenoic, monoenoic and dienoic species, which only accounted for 5% of the mass, represented 80% of the labelled species with either precursor. In one experiment, 90% of this radioactivity was found in the dienoic species. The effect of light on the labelling of the molecular species was examined. Acetate is incorporated primarily into the fatty acids of sulpholipid. Transacylation appears to be important in the interconversion of the molecular species of sulpholipid.