Anti-ORC1 antibodies are used in the immunodetection of the protein origin recognition complex subunit 1. In humans, the canonical protein has a reported length of 861 amino acid residues and a mass of 97.4 kDa. Its subcellular localization is in the nucleus. A member of a the ORC1 protein family, ORC1 is a known component of the origin recognition complex (ORC) that binds origins of replication. Post-translational modifications have been described, including phosphorylation. Synonyms for this target antigen include ORC1L, PARC1, origin recognition complex, subunit 1 homolog, replication control protein 1, and HSORC1.