concept

Chirality

The property of a molecule that exists in two mirror-image forms which cannot be superimposed, exactly like a left and a right hand - the same atoms, the same connections, but arranged in opposite three-dimensional orientations. Because enzymes recognize molecules by their three-dimensional shape, an enzyme can grip only one hand; the mirror form of the same molecule is usually biologically useless. The name comes from the Greek "cheir," hand.