Measurement of latent polyphenol oxidase activity in the presence of the divalent cations Ca +2 , Mg +2 and Mn +2

In the present paper the specific effect of divalent cations on the measurement of the catecholase activity of latent polyphenol oxidase, extracted from Gamay grape suspension cultures, is analysed. The optimum conditions for the activation process produced by the divalent cations have been examined with respect to cation concentration and the pH of the reaction medium. This activation has also been studied with regard to the kinetic parameters of the enzyme in its catalytic expression on 4‐methylcatechol. In order to maximize the catalytic capacity of latent polyphenol oxidase it is necessary to measure the enzymic activity in the presence of divalent cations such as Ca +2 , Mn +2 or Mg +2 .