Reconstruction of Laccase from its Protein and Copper

Abstract

THE conception that oxidases are metallo-protein compounds in which the metal plays an essential part in the catalytic activity of the enzyme was introduced by Gabriel Bertrand¹ in the course of his studies on laccase, the oxidizing enzyme present in the latex of the Indo-Chinese lacquer tree. As crude preparations of laccase contained an appreciable amount of manganese, Bertrand assumed that this metal forms the active part of the oxidase. A more recent study of this problem by Keilin and Mann², based upon highly purified enzyme prepared on a large scale from the latex of different lacquer trees, produced evidence that the active metal is not manganese but copper. This view, however, was challenged by Didier Bertrand³, who claimed to have isolated an enzyme of higher activity which contained 0·15 per cent manganese and only 0·014 per cent copper.