Aromatic biosynthesis in higher plants. 2. Mode of attachment of shikimic acid and dehydroshikimic acid to dehydroshikimic reductase

Abstract

A number of aromatic and hydro-aromatic compounds of similar structure to the natural substrates of dehydroshikimic reductase, shikimic acid and dehydroshikimic acid, were examined for possible inhibition. Several of the compounds found to cause inhibition were examined further, and were shown to inhibit competitvely. The inhibitor constants for these competitive inhibitors were calculated. Since these compounds presumably inhibit by occupying the site normally serving for attachment of shikimic acid and dehydroshikimic acid, a theory of the mode of attachment of the substrates to the enzyme is discussed. It is suggested that shikimic acid and dehydroshikimic acid are attached to the enzyme by means of the carboxyl and 3- and 4-hydroxyl groups.