Chapter 5 Assaying mitochondrial respiratory complex activity in mitochondria isolated from human cells and tissues

Abstract

Publisher Summary This chapter investigates mitochondrial respiratory complex activity in mitochondria isolated from human cells and tissues. Mitochondrial cytopathies are a heterogeneous group of multisystem disorders predominantly affecting skeletal and cardiac muscle and the central nervous system, but are associated with a broad spectrum of other clinical phenotypes, including neurodegenerative disease. In many patients, the impairment of mitochondrial respiratory chain function is due to a mutation in mitochondrial DNA (mtDNA), which may take the form of a rearrangement or a point mutation in a tRNA, rRNA, or protein-encoding gene. Despite major advances in the molecular investigation of patients with disease due to respiratory chain abnormalities, there are still many unresolved problems in the biochemical investigation of patients, and there is frequently a lack of correlation between biochemical and molecular genetic abnormalities. This chapter concludes that accurate biochemical investigation is required for determining the site and severity of the defect along with an understanding of the control that each individual complex has on overall substrate oxidation.