The international journal of biochemistry & cell biology
-
Int. J. Biochem. Cell Biol. · Oct 2009
ReviewCapacity of oxidative phosphorylation in human skeletal muscle: new perspectives of mitochondrial physiology.
Maximal ADP-stimulated mitochondrial respiration depends on convergent electron flow through Complexes I+II to the Q-junction of the electron transport system (ETS). In most studies of respiratory control in mitochondrial preparations, however, respiration is limited artificially by supplying substrates for electron input through either Complex I or II. High-resolution respirometry with minimal amounts of tissue biopsy (1-3mg wet weight of permeabilized muscle fibres per assay) provides a routine approach for multiple substrate-uncoupler-inhibitor titrations. ⋯ The apparent ETS excess capacity (uncoupled respiration) over ADP-stimulated OXPHOS capacity is high in skeletal muscle of active and sedentary humans, but absent in mouse skeletal muscle. Such differences of mitochondrial quality in skeletal muscle are unexpected and cannot be explained at present. A comparative database of mitochondrial physiology may provide the key for understanding the functional implications of mitochondrial diversity from mouse to man, and evaluation of altered mitochondrial respiratory control patterns in health and disease.