The function of ENSG00000198840 (MT-ND3, mitochondrially encoded NADH:ubiquinone oxidoreductase core subunit 3) is as follows. Core subunit of the mitochondrial membrane respiratory chain NADH dehydrogenase (Complex I) which catalyzes electron transfer from NADH through the respiratory chain, using ubiquinone as an electron acceptor (PubMed:25118196). Essential for the catalytic activity of complex I (PubMed:25118196). .