3-deoxy-d- arabino-heptulosonate 7-phosphate synthase from pea leaves: Inhibition by L-tyrosine

Abstract

Regulation of 3-deoxy-D- arabino-heptulosonate 7-phosphate (DAHP) synthase from Pisum sativum L. is similar to the unimetabolite type of control of the enzyme from blue-green algae. In leaf extracts about 85% of the enzyme activity was inhibited by L-tyrosine. At substrate concentration of 1 mM phosphoenolpyruvate (PEP) and 2 mM erythrose 4-phosphate (E4P) the end-product sensitive activity was inhibited by 50% at about 1 mM L-tyrosine. Unlike the enzyme from blue-green algae, inhibition of the enzyme from pea could be relieved by L-phenylalanine and L-tryptophan.