Tetrameric protein

For other uses, see Tetramer.
two protein subunits bind to form a dimer. Two dimers then bind to form the final tetramer.
The formation of the sorbitol dehydrogenase tetramer from its monomers via dimers.

A tetrameric protein is a protein with a quaternary structure of four subunits (tetrameric). Homotetramers have four identical subunits (such as glutathione S-transferase), and heterotetramers are complexes of different subunits. A tetramer can be assembled as dimer of dimers with two homodimer subunits (such as sorbitol dehydrogenase), or two heterodimer subunits (such as hemoglobin).