A novel method for the measurement of in vitro fatty acid 2-hydroxylase activity by gas chromatography-mass spectrometry

Journal of Lipid Research

Nathan L. Alderson¹  Michael D. Walla²  Hiroko Hama³ 

[1] Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, SC 29425;Department of Chemistry and Biochemistry, University of South Carolina, Columbia, SC, 29208;To whom correspondence should be addressed.;

关键词: FA2H;    fatty acid alpha-hydroxylase;    2-hydroxy fatty acid;   

DOI  :  

来源: DOAJ

【 摘 要 】

Fatty acid 2-hydroxylase (FA2H), encoded by the FA2H gene, is an enzyme responsible for the de novo synthesis of sphingolipids containing 2-hydroxy fatty acids. 2-Hydroxy sphingolipids are highly abundant in the brain, as major myelin galactolipids (galactosylceramide and sulfatide) contain a uniquely high proportion (∼50%) of 2-hydroxy fatty acids. Other tissues, such as epidermis, epithelia of the digestive tract, and certain cancers, also contain 2-hydroxy sphingolipids. The physiological significance of the 2-hydroxylation on N-acyl chains of subsets of sphingolipids is poorly understood. To study the roles of FA2H and 2-hydroxy sphingolipids in various tissues, we developed a highly sensitive in vitro FA2H assay. FA2H-dependent fatty acid 2-hydroxylation requires an electron transfer system, which was reconstituted in vitro with an NADPH regeneration system and purified NADPH:cytochrome P-450 reductase. A substrate [3,3,5,5-D4]tetracosanoic acid was solubilized in α-cyclodextrin solution, and the 2-hydroxylated product was quantified by gas chromatography-mass spectrometry after conversion to a trimethylsilyl ether derivative. When the microsomes of FA2H-transfected COS7 cells were incubated with the electron transfer system and deuterated tetracosanoic acid, deuterated 2-hydroxy tetracosanoic acid was formed in a time- and protein-dependent manner.With this method, FA2H activities were reproducibly measured in murine brains and tissue culture cell lines.

【 授权许可】

Unknown