Background：NDUFA3 （NADH dehydrogenase （ubiquinone） 1 alpha subcomplex, 3）, also known as B9, is one of about 45 subunits comprising Complex I of the oxidative phosphorylation electron transport chain. Consisting of 84 amino acids and belonging to the Complex I NDUFA3 subunit family, NDUFA3 functions as an accessory subunit of the multi-protein mitochondrial membrane respiratory chain NADH dehydrogenase complex （known as Complex I）. Complex I plays an important role in the transfer of electrons from NADH to the respiratory chain, a process that is essential for cellular respiration.
