metabolomer

Metabolomer is a term used in chemistry and metabolomics to describe an isomeric form of a metabolite produced during metabolism. The word combines metabolism and isomer, indicating structural variants that share the same molecular formula but differ in connectivity or stereochemistry as a result of enzymatic or chemical transformations in biological systems.

Metabolomers can be configurational isomers (such as enantiomers and diastereomers) or constitutional and tautomeric isomers arising from rearrangements or proton transfers. They may interconvert under certain conditions and can be produced by specific enzymes such as isomerases, mutases, or epimerases, as well as through non-enzymatic processes in vivo or in vitro.

Characterization typically relies on high-resolution mass spectrometry and nuclear magnetic resonance, often coupled with chromatographic separation to resolve isomeric species. The concept helps explain part of the metabolic chemical space not captured when only a single canonical metabolite is considered, and it has implications for metabolomics databases, drug metabolism, and toxicology, since different metabolomers can have distinct biological activities or clearance rates.

Illustrative examples include epimers of a sugar-derived metabolite that differ at a single stereocenter, or keto–enol tautomer pairs of a metabolic intermediate stabilized differently by cellular conditions. The prevalence and practical utility of the term vary across fields, and it remains a topic of discussion in methodological reviews.

See also: metabolite, metabolome, isomer, stereoisomer, epimer, mutase, isomerase.