Asked by John

What is a dimer

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Answered by GPT-5 mini AI
A dimer is a molecule or molecular complex made of two subunits (called monomers) that are chemically or physically joined.

Key points
- Homodimer vs heterodimer: a homodimer is formed from two identical monomers; a heterodimer from two different ones.
- Bonding: the two units can be joined by covalent bonds (e.g., disulfide-linked protein dimers) or by noncovalent interactions (hydrogen bonds, ionic interactions, van der Waals forces).
- Contexts and examples:
- Biochemistry: many proteins act as dimers (receptors, enzymes); dimerization often affects activity, specificity, or stability.
- DNA damage: thymine dimers are covalent links between adjacent pyrimidines caused by UV light.
- Small molecules: carboxylic acids can form hydrogen-bonded dimers; in organic synthesis, “dimerization” can produce a two-unit product (e.g., two alkenes joining).
- Significance: forming a dimer can change physical and chemical properties (solubility, reactivity, biological function).
- In polymer chemistry, a dimer is the simplest oligomer (degree of polymerization = 2).

If you want, I can give specific examples (protein, organic, or DNA thymine dimers) or explain how dimerization is studied experimentally.