THE PRIMARY AND SECONDARY COMPOUNDS OF CATALASE AND METHYL OR ETHYL HYDROGEN PEROXIDE IV. REACTIONS WITH HYDROGEN PEROXIDE* BY BRITTON CHANCEt

Stern (1) has found that as much as 0.13 N ethyl hydrogen peroxide is required to give 50 per cent inhibition of the destruction of hydrogen peroxide by catalase. This is difficult to understand in view of the high affinities of catalase for ethyl hydrogen peroxide in both the primary and secondary compounds (~2 X 10” M) (2), in which all the catalase hematins are bound to ethyl hydrogen peroxide (3). Stern (1) also tested the inhibition of catalase activity by methyl hydrogen peroxide but found that methyl hydrogen peroxide disappeared in some unexplained fashion. Since the activity of catalase is inhibited at a concentration of cyanide predicted by the spectrophotometric equilibrium constant (4) and both cyanide and peroxide attach to the iron atom of catalase (3), there must be some reaction which is responsible for the small inhibition by the alkyl hydrogen peroxides. This paper describes a rapid reaction of hydrogen peroxide and catalase-bound alkyl hydrogen peroxide and presents some mechanisms for catalase activity.