Novel Detection System for Calcium(II) Ions Based on an Apoenzyme Reactivation Method Using an Amylase Column as a Recognition Element

A flow-injection amperometric system for evaluation of the activity of an immobilized α-amylase column was constructed and the system was applied to detect of calcium (II) ions based on the apoenzyme reactivation method. The α-amylase activity was amperometrically evaluated by using a double-layered column which consisted of α-glucosidase and pyranose oxidase. The detection of calcium (II) ions, being the cofactor of α-amylase, was realized by measuring the reactivation of apo-type α-amylase column, which was the recognition element of Ca(II) ions. Maleate buffer (0.1 M, pH 6.0) as a carrier solution was continuously pumped through the system, and sample solutions were introduced into the system via rotary injection valves. The catalytic activity of the multi-enzyme column was assessed by injecting 0.5% starch solution as a substrate. Calcium(II) ions in 1.0 mM levels were detected by using the system based on the apoenzyme reactivation method.