The entatic state.

Abstract

Vallee and Williams (1968) defined the entatic state as an abnormal condition of a region of a protein which had arisen through the internal activation of this region by geometric and/or electronic strain. This strain was considered to be due to the conformational demands which gave stability to other parts of the protein, the whole being at a minimum free energy. A diagram illustrating the rate enhancement gained by the activation of the special region of the protein is shown in Fig. 1, which is to be contrasted with the conventional diagram for enzyme catalysis, Fig. 2. It may be clearer to state that the entatic region of the enzyme has suffered a unimolecular activation of its groups relative to the state of these groups in a randon-coiled protein. The customary analysis (Fig. 2) refers to a stabilization of the transition state of a bimolecular complex. In many respects, then,...