Anti-OBI1 antibodies are used in the immunodetection of the protein ORC ubiquitin ligase 1. In humans, the canonical protein has a reported length of 726 amino acid residues and a mass of 81.1 kDa. Its subcellular localization is in the chromosomes. It is notably widely expressed in many tissue types. OBI1 is known to be involved with DNA replication. Post-translational modifications have been described, including ubiquitination. Synonyms for this target antigen include ring finger protein 219. OBI1 gene orthologs have been reported in the mouse, rat, bovine, frog, zebrafish, chimpanzee and chicken species.