Effect of silicon compounds on plant enzymes involved in phosphorus metabolism

Abstract

Both ionic silicate and colloidal silica exhibited an appreciable inhibitory effect on acid phosphatase of potato tubers and rice plant leaves, but not on acid phosphatase of sweet potato roots and yeast hexokinase. Inhibition of the potato phosphatase by ionic silicate is of the competitive type, and the enzyme has a K m of 4.0 × 10 −4 M for p-nitrophenyl phosphate, and K i of 1.5 × 10 −3 M for ionic silicate. Neither ionic silicate nor colloidal silica had an appreciable inhibitory effect on the oxidative phosphorylation of sweet potato mitochondria.