Figure 5.

Central illustration: the impact of obesity on myocardial ATP transfer through the creatine kinase system. Creatine kinase facilitates rapid transfer of ATP from mitochondrion to myofibril by using rapid diffusion of phosphocreatine (Top left), enabling increased ATP delivery in response to demand (Top right). As body mass index increases, creatine kinase kinetics increase, compensating for falling PCr/ATP, and maintaining ATP delivery at rest (Bottom left); however, this increase comes at the cost of a blunted response to stress (Bottom right). CK_cyto indicates cytosolic creatine kinase; CK_mito indicates mitochondrial creatine kinase; Cr, creatine; P, phosphate group; and PCr, phosphocreatine.