A Reduced Diphosphopyridine Nucleotide Oxidase in Lettuce Seeds

Abstract

VARIOUS enzymes oxidizing reduced diphosphopyridine nucleotide by pathways other than the cytochrome system have been described. Kern and Racker¹ indicated an oxidase dependent on a product of the oxidation of ascorbic acid, and Nason et al.² have shown the existence of a nucleotide–quinone reductase. Mapson and Moustafa³ have shown the oxidation of reduced triphosphopyridine nucleotide by an enzyme linked to glutathione, while Kersten et al.⁴ have demonstrated the existence of an oxidase dependent on ascorbic acid. Hackett⁵ has shown that the ascorbic acid oxidase of potato tubers can oxidize reduced diphosphopyridine nucleotide. Dry lettuce seeds seem to contain an enzyme which does not correspond to those previously described.