homomerism

Homomerism is the property by which a molecule or complex consists entirely of identical units or subunits. In polymer chemistry, a homomer is more commonly called a homopolymer, a polymer formed from a single type of monomer repeated along the chain. In biochemistry, the term is used for protein complexes composed of multiple copies of the same polypeptide; such assemblies are described as homomeric oligomers, with the number of subunits denoted as the oligomeric state (e.g., dimers, trimers, tetramers). By contrast, heteromerism refers to assemblies containing two or more different subunits.

Homomeric assemblies are characterized by symmetry, which influences assembly pathways and functional properties. Structural studies show that homomers often adopt cyclic (Cn) or dihedral (Dn) symmetry and, in larger complexes, higher-order symmetries such as icosahedral. The repeated, identical subunits can confer cooperative behavior, stability, and uniform functional interfaces. Many enzymes, channels, and transporters form homomeric architectures, though many also function as heteromers.

Techniques such as X-ray crystallography, cryo-electron microscopy, and mass spectrometry help establish whether a complex is homomeric and reveal its arrangement. Understanding homomerism has implications for protein design, nanotechnology, and the study of diseases arising from misassembly.