ep'i-mĕr One of two molecules (having more than one chiral center) differing only in the spatial arrangement about a single chiral atom, for example, α-d-glucose and α-d-galactose (with respect to carbon-4). See also: sugars. Compare: anomer. [epi- +
either of a pair of isomeric aldose compounds, especially of certain sugars, that differ from each other in the positions of the H and OH at the second atom from the end of the carbon chain, as d-glucose and d-mannose.