Heterotetramer

A heterotetramer is protein containing four non-covalently bound subunits, wherein the subunits are not all identical. A homotetramer contains four identical subunits.

Examples include haemoglobin (pictured), the NMDA receptor, some aquaporins, some AMPA receptors, as well as some enzymes.

Ion-exchange chromatography is useful for isolating specific heterotetrameric protein assemblies, allowing purification of specific complexes according to both the number and the position of charged peptide tags.Nickel affinity chromatography may also be employed for heterotetramer purification.

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