TABLE 3.
Relative percent 13C enrichment in acyl-CoA mass isotopomers produced from [1,2,3,4-13C4]palmitic acid (M+4) in perfused hearts
Rat heart extracts were analyzed for acyl-CoAs by UHPLC-MS/MS, using multiple reaction monitoring transitions specific to the isotopic form of each acyl-CoA species. The deconvolution of the isotope patterns was performed using the “Isopat” algorithm of Gruber et al. (21). The data represent the mean ± S.E. of six experiments. Boldface identifies the mass isotopomers whose percent 13C enrichment is expected to be altered due to β-oxidation/chain elongation of perfused [1,2,3,4-13C]palmitate (M+2, M+4, M+6) or by dilution by endogenous fatty acids (M+0).
| Palmitoyl-CoA | Myristoyl-CoA | Stearoyl-CoA | Mitochondrial acetyl-CoA (citrate) | Total Acetyl-CoA | Malonyl-CoA | |
|---|---|---|---|---|---|---|
| M+0 | 4.2 ± 0.8 | 8.2 ± 1.1 | 53.6 ± 11.5 | 81.1 ± 0.8 | 77.6 ± 0.9 | 80.0 ± 1.0 |
| M+1 | 0.0 | 1.2 ± 0.13 | 0.4 ± 0.53 | 0.2 ± 0.05 | 0.1 ± 0.05 | 1.3 ± 0.2 |
| M+2 | 0.3 ± 0.14 | 93.4 ± 1.2a | 2.5 ± 0.63 | 18.9 ± 0.8a | 22.4 ± 0.9a | 19.9 ± 1.1a |
| M+3 | 2.3 ± 0.03 | 0 | 0.8 ± 0.25 | 0.0 | 0.0 | 0.0 |
| M+4 | 93.2 ± 0.74a | 0 | 37.8 ± 10.1a | 0.0 | 0.6 ± 0.03 | 0.0 |
| M+5 | 0.0 | 0.1 ± 0.1 | 0.0 | |||
| M+6 | 3.8 ± 0.12 | 5.4 ± 1.6a,b | ||||
| M+7 | 0.0 | |||||
| M+8 | 0.0 |
a p < 0.05 versus M+0.
b p < 0.05 M+6 versus M+4 and M+0 (analysis of variance).