The function of NDUFA3 (NADH:ubiquinone oxidoreductase subunit A3, Ensembl gene identifier ENSG00000170906) is as follows. Accessory subunit of the mitochondrial membrane respiratory chain NADH dehydrogenase (Complex I), that is believed not to be involved in catalysis. Complex I functions in the transfer of electrons from NADH to the respiratory chain. The immediate electron acceptor for the enzyme is believed to be ubiquinone. .