The roles of Na+ and K+ in pyridoxal phosphate enzyme catalysis

The group I monovalent cations Na+ and K+ and ammonium ion are important effectors of catalytic activity for a wide variety of enzymes. Until recently, little was known about the mechanism of action of these effectors. However, in the past year, X-ray structures of three metal-ion-activated pyridoxal phosphate (PLP)-requiring enzymes have been solved. This information together with solution studies of these and related enzymes have provided new...