"In 1954, Novick and Szilard discovered that the synthesis of a tryptophan precursor‥was inhibited by tryptophan.‥ The work of Umbarger‥demonstrated that, in many pathways, an early enzyme is so constructed as to be strongly and specifically inhibited by the‥endproduct.‥ The most remarkable feature of the Novick-Szilard-Umbarger effect is that the inhibitor is not a steric analogue of the substrate. We propose therefore to designate this mechanism as ‘allosteric inhibition’" (OED).