Mechanism of Enzyme Specificity in the Domain of Carbohydrates

Abstract

IT would appear that it is the function of enzymes to reduce the energy of activation for a given reaction. How this is effected is at present unknown. There is, however, consensus of opinion that enzyme action is initiated by a union between enzyme and substrate. Bergmann¹ has advanced the theory that the enzyme protein by virtue of polar groups arranged in a pattern at its surface makes a multipoint contact with corresponding polar groups of the substrate. An intimate relationship of this kind between the interacting groups, suitably arranged in space, of enzyme and substrate may be regarded as the material basis of enzyme specificity. In most cases a single enzyme reacts with a group of substrates, though at different rates; in some cases, however, the activity of the enzyme is directed towards one substrate only. The degree of specificity of an enzyme may most properly be expressed by the decrease in the reaction velocity caused by a change in the constitution or configuration of that substrate acted upon with the highest reaction velocity (at various substrate concentrations). During the last fifteen years the effect of constitutional and configurational changes in hexoses and their glycosidic derivatives on the activity of the enzyme concerned has been extensively investigated. In view of the results of these investigations, it seems possible to derive some principles underlying enzyme specificity in the field of carbohydrates and in some instances to mark precisely the atoms or groups of the substrate which are involved in the bonding with the receiving groups of the specific enzyme protein.