Effects of Phytic Acid, Divalent Cations, and Their Interactions on α‐Amylase Activity

Abstract

ABSTRACT The effects of phytic acid and its interactions with divalent cations (Ca ++ and Mg ++ ) on α‐amylase activity were investigated in model systems. Amylase activity was influenced by both preincubation time with phytate as well as phytate concentration. At 6‐30 mM concentrations, Ca ++ and Mg ++ ions lowered the enzyme activity by 9‐34% and 24‐49%, respectively. When divalent cations were added simultaneously with phytate, a slight increase in enzyme activity with Ca ++ and lowered enzyme activity with Mg ++ were observed, as compared to when added independently. The enzyme activity was only moderately lowered when phytate was first preincubated with the divalent cations. Amylase inhibition by phytate was found to be of noncompetative type with an apparent inhibitor constant of 1.75 mM under the assay conditions.