Figure 2. Mitochondrial enzyme content of soleus and gastrocnemius muscles of sedentary or active, WT or CK^−/− mice.

Citrate synthase (CS) is an enzyme of the Krebs cycle and cytochrome c oxidase (COX) is the complex IV of the respiratory chain. Small changes in mitochondrial enzyme activities are observed in soleus, both in response to CK deficiency and activity. In gastrocnemius muscle, a dramatic increase in mitochondrial enzymes is present in CK deficiency in both sedentary and active animals. *P < 0.05; ***P < 0.001. *Significantly different from control mice.