Synthesis and characterization of fluorescent neutral lipid analogs containing N-(7-nitro-2,1,3-benzoxadiazol-4-yl)-aminohexanoic acid.

J C McIntyre, D Watson, R G Sleight

Index: Chem. Phys. Lipids 66(3) , 171-80, (1993)

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Abstract

The synthesis, identification and characterization of neutral lipid analogs containing N-(7-nitro-2,1,3-benzoxadiazoi-4-yl)-aminocaproic acid are reported. The acyl-imidazole derivative of the fluorescent fatty acid was used to esterify L-alpha-glycerophosphorylcholine. Fluorescent phosphatidylcholines were converted to the corresponding diacylglycerols by phospholipase C digestion. Triacylglycerols were formed by esterification with either fluorescent fatty acid-imidazole or non-fluorescent fatty acid anhydride. The 11 compounds synthesized were identified by a combination of thin layer chromatography, liquid secondary ion mass spectrometry and enzymatic digestion. A solvent system for identifying all eleven analogs by thin layer chromatography is presented. The fluorescence characteristics of these analogs are consistent with previously observed parameters of NBD-lipid analogs, including the density-dependent quenching of analogs containing multiple NBD fluorophores. These analogs mimic native lipids, as evidenced by digestions with the enzymes, porcine pancreatic lipase, phospholipase C and phospholipase A2.