Mitochondrial DNA Mutations and Diseases

摘要

Mitochondria are animal cellular organelles whose major function is to utilize the molecular oxygen to convert the chemical energy in sugars and fatty acids into ATP, the cellular energy currency. This process is called oxidative phosphorylation (OXPHOS), in which, the NADH and FADH2 produced through TCA cycle and fatty acid beta-oxidation in mitochondria are oxidized. Electrons from these reducing agents are going through the electron transport chain and finally given to oxygen, creating a proton-gradient, which drives ATP synthesis. Most patients with mitochondrial disorders have molecular defects affecting the mitochondrial OXPHOS system, consisting of - 87 protein subunits, forming five multi-protein complexes (complex I to V) embedded in the inner mitochondrial membrane. Among these 87 proteins, 13 are encoded by the mitochondrial genome and the remaining are encoded by the nuclear genome.