FIGURE 2.

Energy production and transfer in adult cardiomyocyte. Fatty acids are far and away the main substrates for energy production of the adult cardiomyocyte when the relative contribution of carbohydrate is much smaller than in the fetal cardiomyocyte. About 90% of energy is provided by oxidative phosphorylations taking place in mitochondria. The major part of ATP produced by mitochondria is transformed into phosphocreatine (PCr) by mitochondrial creatine kinase (CK) which initiates energy transfer to energy consumers using the CK shuttle to overcome diffusion issue resulting from the packed intracellular organization of the adult cardiomyocyte. This complex intracellular architecture allows the emergence of energy micro-domains in which adenine nucleotides are directly exchanged between mitochondria and energy consumers (DANC).