A Prospect for the Analysis of Species Acting as Enzyme Inhibitors as Illustrated by Heavy Metal Inhibition

Abstract

A flow system incorporating an amperometric glucose oxidase enzyme electrode has been used to study the inhibitory effects of 16 metal cations on glucose oxidase. Only copper(II), mercury(II) and silver(I) caused any significant inhibition. the enzyme electrode could be reactivated by EDTA, the reactivation being most effective for copper(II) and least so for silver(I). Other complexing agents were tried for reactivation but proved to be unsatisfactory. The ability to reactivate the enzyme on the electrode following copper(II) inhibition, and the linear response of the system to the level of this inhibitor according to I/A = -9.49 × 10⁻⁷ log([Cu]/M) + 4.84 × 10⁻⁸; r = 0.994 between 2.5 × 10⁻⁴M and 5 × 10⁻³M [Cu]²⁺ indicates a prospect for the use of a flow system for determining enzyme inhibitors in samples.