Molecular Mechanisms of Enzyme Activation by Monovalent Cations

Regulation of enzymes through metal ion complexation is widespread in biology and underscores a physiological need for stability and high catalytic activity that likely predated proteins in the RNA world. In addition to divalent metals such as Ca2+, Mg2+, and Zn2+, monovalent cations often function as efficient and selective promoters of catalysis. Advances in structural biology unravel a rich repertoire of molecular mechanisms for enzyme activation by Na+ and K+. Strategies range from short-range effects mediated by direct participation in substrate binding, to more distributed effects that propagate long-range to catalytic residues. This review addresses general considerations and examples.