Component of a multicomponent complex - for example, one protein component of a protein complex.
an ADP-ribosyl transferase that catalyzes the transfer of ADP ribose moiety (ADPR) from NAD to a guanosine triphosphate (GTP)-binding protein that regulates adenylate cyclase activity
A distinct polypeptide chain within a protein that may be separated from other chains (whether identical or different) without breaking covalent bonds.
A single unit of a multi-subunit protein.
One of the pieces that forms a part of a multi-component structure. A link in a chain or a brick in a wall.