Anti-selenoprotein O antibodies are used in the immunodetection of the protein encoded by the SELENOO gene. In humans, the canonical protein has a reported length of 669 amino acid residues and a mass of 73.5 kDa. Its subcellular localization is in the mitochondria. A member of the SELO protein family, it is known to catalyze the transfer of adenosine 5'-monophosphate (AMP) to Ser, Thr and Tyr residues of target proteins (AMPylation). Other names for this target antigen include protein adenylyltransferase SelO, mitochondrial.