Eutomer

Part of speech: noun

Definitions

1. A particular isomer characterized by enhanced biological potency relative to its isomeric counterpart
2. This isomer is defined by its superior efficacy in biological interactions when compared to the alternative stereoisomer
3. A specific isomer distinguished by its greater effectiveness in biological activity compared to its less potent isomer counterpart

Etymology: "Eutomer" is a technical coinage from pharmacology and chemistry, built from the Greek prefix "eu-", meaning "well" or "good", and "enantiomer". An enantiomer is one of a pair of molecules that are mirror images of each other, like left and right hands, and that cannot be superimposed on one another. The "eu-" prefix marks the member of the pair that does the job better. The idea behind the word is that a drug molecule often has two such mirror-image forms, and the body, whose receptors and enzymes are themselves shaped asymmetrically, may respond to one far more strongly than the other. The more active form is the eutomer, and the weaker form is its distomer, built on the Greek "dys-", meaning "bad" or "difficult." Because the two halves of the pair are chemically identical except for their handedness, the distinction only becomes visible in biological settings.