A trimer (v. Greek. Trimeric , three-piece ') is a molecule consisting of three subunits, the monomers , there is. The chemical reaction to form a trimer is called trimerization (also trimerization; examples there). The trimer is therefore the structure following the dimer on the way from a monomer via oligomers to the polymers .
If a trimer consists of identical subunits, it is referred to as a “homotrimer”, “homotrimeric compound”, “homotrimeric complex” or the like. If different subunits form the trimer, the terms “heterotrimer”, “heterotrimeric compound”, “heterotrimeric complex” or the like are also used.
Designations of higher oligomers, for example tetramer or pentamer , are usually no longer named as such with these number words, but can be used in individual cases - such as with protein complexes in biochemistry .