Accessory subunit of the mitochondrial membrane respiratory chain NADH dehydrogenase (Complex I), that is believed not to be involved in catalysis (PubMed:27626371, PubMed:32385911, PubMed:33153867). Complex I functions in the transfer of electrons from NADH to the respiratory chain (PubMed:27626371). The immediate electron acceptor for the enzyme is believed to be ubiquinone (PubMed:27626371).
