Anti-Np15 antibodies enable researchers to detect and measure the Np15 antigen in biological samples. This target is a reported synonym of the NDUFB11 gene, which encodes NADH:ubiquinone oxidoreductase subunit B11. This protein is reported to be an accessory subunit the mitochondrial membrane respiratory chain NADH dehydrogenase (Complex I), that is believed not to be involved in catalysis. The human version of Np15 has a canonical amino acid length of 153 residues and a protein mass of 17.3 kilodaltons, although 2 isoforms have been identified. It is reported to be localized in the mitochondria of cells and widely expressed in many tissue types. Other names for this target antigen include CI-ESSS, ESSS, and MC1DN30.