Occurrence of a Novel Enzyme, L-Lysine Oxidase with Antitumor Activity in Culture Extract of Trichoderma viride

Abstract

An aqueous extract of culture of Trichoderma viride Y244-2 on wheat bran showed antitumor activity against L5178Y mouse leukemic cells in vitro and L1210 mouse leukemia in vivo. The principle of the antitumor activity was proved to be an L-lysine-oxidizing enzyme. Oxygen consumption was accompanied by the formation of α-keto acid, ammonia and hydrogen peroxide in the enzyme reaction with L-lysine. The ratio of amount of oxygen consumed to those of α-keto acid and ammonia formed in the presence of catalase was approximately 1:2:2. This enzyme is an L-amino acid oxidase which is highly specific for L-lysine. Thus, we designated it as L-lysine oxidase. Identity of the antitumor substance with the enzyme was confirmed by DEAE-cellulose column chromatography: the elution pattern of growthinhibitory activity against L5178Y cells coincided with that of L-lysine oxidase activity.