Annals of Botany Phosphoenolpyruvate carboxylase activation by reversible phosphorylation in white lupin cluster roots Phosphoenolpyruvate carboxylase (PEPC) is a tightly regulated enzyme that controls carbohydrate partitioning to organic acid anions (malate, citrate) that are excreted in copious amounts by cluster (proteoid) roots of... botanyoneOctober 25, 2016