Identifying Sources of Hepatic Lipogenic Acetyl-CoA Using Stable Isotope Tracers and NMR
Figure 1
Sampling the enrichment of mitochondrial and cytosolic [2-13C]acetyl-CoA isotopomer from [2-13C]acetate by analysis of downstream metabolic intermediates. Mitochondrial acetyl-CoA enrichment may be inferred by analysis of ketone body 13C-isotopomers and the 13C-isotopomer distribution in glutamate carbons 4 and 5. Cytosolic acetyl-CoA isotopomer enrichment may be sampled by acetylation probes such as p-amino benzoic acid (PABA) or by isotopomer analysis of the terminal methyl and methylene 13C-isotopomer distributions of the palmitate product. Note that cytosolic and mitochondrial acetyl-CoA pools may be enriched to different levels depending on the relative activities of mitochondrial and cytosolic acetyl-CoA synthase (ACSS1 and ACSS2, resp.).
