| Autor: |
Wang DH; Division of Nutritional Sciences and Department of Food Science, Cornell University, Ithaca, New York 14850, United States., Park HG; Division of Nutritional Sciences and Department of Food Science, Cornell University, Ithaca, New York 14850, United States., Wang Z; Division of Nutritional Sciences and Department of Food Science, Cornell University, Ithaca, New York 14850, United States., Lacombe RJS, Shmanai VV; Institute of Physical Organic Chemistry, National Academy of Science of Belarus, 13 Surganova Street, Minsk 220072, Belarus., Bekish AV; Institute of Physical Organic Chemistry, National Academy of Science of Belarus, 13 Surganova Street, Minsk 220072, Belarus., Schmidt K; Retrotope Inc., Los Altos, California 94022, United States., Shchepinov MS; Retrotope Inc., Los Altos, California 94022, United States., Brenna JT; Division of Nutritional Sciences and Department of Food Science, Cornell University, Ithaca, New York 14850, United States. |
| Abstrakt: |
No general method currently is available for the quantitative determination of deuterium (D) at C positions along a hydrocarbon chain. Bis -allylic deuterated highly unsaturated fatty acids (D-HUFA) are a novel class of drugs stabilized against H-abstraction-mediated oxidation by deuteration at the most labile positions. Ru-based catalytic deuteration overcomes the limited scale of bis -allylic D-HUFA production by total organic synthesis; however, it produces a complex mixture of bis -allylic D isotopologues and isotopomers, requiring detailed sequencing for characterization. We report here adaptation and application of the Paternó-Büchi (PB) reaction of 2-acetylpyridine to a series of D-HUFA with analysis by shotgun lipidomics to determine position-specific quantitative D abundances. Sodiated PB D-HUFA result in diagnostic ions of high abundance upon collision-induced dissociation (CID) activation, enabling sensitive differentiation and quantification of D fraction at each bis - and mono -allylic position for each isotopologue. Catalytically deuterated isotopologues D5-7 linolenic acid (D5-7 LnA), D6-8 arachidonic acid (D6-8 ARA), D7-9 eicosapentaenoic acid (D7-9 EPA), and D9-11 docosahexaenoic acid (D9-11 DHA) incorporate 80-98, 95-100, 81-100, and 83-100% D at their bis -allylic positions, respectively. D-HUFA isotopologues having D number greater than or equal to bis -allylic sites (e.g., D10-DHA or D11-DHA) deuterated >95% at bis -allylic positions, except for D-LnA. The mono- allylic position near the methyl end deuterates to a much greater extent than the mono- allylic position near the carboxyl end, and both positions deuterate only when bis -allylic D is near-saturated. This method enables rapid, accurate characterization of position and isotopomer-specific D composition and enables sequencing along the chain. |
