Oxidation of ascorbic acid by plant extracts

Abstract

That the catalytic agency responsible for vitamin C oxidation in plant extracts is a specific copper-protein enzyme has been shown by several workers. There is, however, disagreement as to whether the oxidase activity is exerted by this complex, or by the ionized copper from it. Active preparations of artificial oxidases, with ionic copper as the responsible constituent, have been reported. On the other hand, purified preparations of the enzyme have been found to oxidize ascorbic acid many times faster than an equivalent quantity of cupric ion.