Figure 1.

(A) Overview of the acetate metabolism: Acetate enters the cytosol where it gets converted to acetylCoA via acetyCoA synthetase (ACS). Then acetylCoA gets converted via carnitineacetyltransferase (CAT)-1 to acetylcarnitine, which can be shuttled into the mitochondria. There it can be metabolized in the TCA cycle, transformed back to acetylCoA via CAT-2. In diabetes myocardial CAT-1 activity is increased, which is a crucial step for myocardial fuel selection. (B) Acetylation of CoA via ACS. (C) CAT catalyses the formation of free CoA and ALCAR. (D) The enzyme activities of acetylCoA carboxylase (ACC) and malonylCoA decarboxylase (MCD) balance the activity of CAT-1. MCD is more active under diabetes, leading to more decarboxylation of malonylCoA, the lowered malonylCoA concentration leads to less inhibition of CAT-1. (E) Schematic spectrum showing the ¹³C chemical shifts of the molecules occurring in the metabolism of [1-¹³C]acetate.