Hormonal modifications of plant citrate synthase [formula omitted

Abstract

Citrate synthase (EC 4.1.3.7.) from roots of bean seedlings and mitochondria of cauliflower buds was purified 400-fold and had specific activity of 6 to 10. Such enzyme was stimulated by the plant hormone indoleacetic acid (IAA). Consistent with the accepted molecular size of the enzyme, it was eluted as a single peak off Sephadex G-200. Treatment with IAA increased the molecular size of the enzyme. It is demonstrated that while increasing its activity and modifying its size, the hormone binds with the enzyme.