THE ENZYMATIC REDUCTION OF TETRAZOLIUM SALTS BY AMINES

Abstract

An enzyme system effecting the dehydrogenation of amines has been detected in rat brain and liver suspensions by the use of tetrazolium dyes as terminal electron acceptors. Kinetic data on this system are presented and the evidence for requirement of a cofactor is described. Thus, after washing or dialysis, rat brain suspensions have a considerably lowered tetrazolium reducing activity, which can be restored by addition of boiled extracts of rat liver, rat brain, pig liver, or baker's yeast. The heat-stable cofactor in pig liver and rat brain which is necessary for the activity of the tetrazolium reducing system is dialyzable. Pig liver extracts lose their cofactor activity on ashing. The nature of the electron transporting system active in amine dehydrogenation is discussed and the properties of the tetrazolium reducing and the amine oxidase systems are compared.