title: Chiral 1,2-diacylglycerols in the haemolymph of the locust, Locusta migratoria.
abstract: A 1H-NMR method using chiral shift reagents was applied in the stereochemical analysis of the haemolymph 1,2-diacylglycerols of Locusta migratoria. Conversion of the 1,2-diacylglycerols into 1,2-diacetyl-3-tritylglycerols allowed the accurate determination of the enantiomeric purity, whereas direct trimethylsilylation of the unmodified or hydrogenated haemolymph 1,2-diacylglycerols proved to be less suitable because of signal broadening. In the haemolymph of Locusta, sn-1,2-diacylglycerols with a remarkably high optical purity were found to be present. In the resting locust, at least 96% of the haemolymph 1,2-diacylglycerols have the sn-1,2-configuration, in locusts in which the haemolymph diacylglycerol concentration was elevated by fat body triacylglycerol mobilization induced by flight activity or injection of adipokinetic hormone, over 97% of the 1,2-diacylglycerols is the sn-1,2-enantiomer. The few percent sn-2,3-enantiomer may not have been present initially. Positional distribution of the fatty acids in the fat body triacylglycerols and in the haemolymph sn-1,2-diacylglycerols obtained from locusts after a 2 h flight revealed nearly identical occupation of the sn-2-positions in both acylglycerols. The distribution patterns in the sn-1-position of the 1,2-diacylglycerols and the combined sn-1 and sn-3 positions of the triacylglycerols are compatible with the possible existence of a stereospecific sn-3-triacylglycerol lipase.
mesh_terms: D000818:Animals; D004075:Diglycerides / Q000097:blood*; D005216:Fat Body / Q000032:analysis; D005426:Flight, Animal; D005989:Glycerides / Q000097:blood*; D006110:Grasshoppers / Q000378:metabolism*; D006458:Hemolymph / Q000032:analysis*; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D012146:Rest; D013237:Stereoisomerism
chemical_list: D004075:Diglycerides; D005989:Glycerides