Determination of traces of copper by activation of water-insoluble apopolyphenol oxidase

Abstract

Polyphenol oxidase is insolubilised by chemical bonding to polyacrylamide. Copper is removed from the enzyme, and the resulting apoenzyme may be reproducibly and very selectively reactivated by incubation with 10–200 ng of copper(II), the extent of activation being a measure of copper concentration. The properties of the insoluble apoenzyme are described; the effect of other metal ions on copper activation or on the apoenzyme itself are minimal until their concentration is more than 1000 times that of copper.