what do you need to do to be sure turnip peroxidase is responsible for the color change of guaiacol and not some other turnip enzyme

Purify peroxidase through metal affinity chromatography

Explanation:

In order to make sure the turnip peroxidase is responsible for the color change of guaiacol and not some other turnip enzyme it would be necessary to purify peroxidase through metal affinity chromatography. For the change of color some factors need to be appreciated too, pH, enzyme concentration and temperature will influence the reaction. Peroxidase is a heme, an enzyme encouraged of the catalyze reaction of hydrogen peroxide.