INHIBITION BY STREPTOMYCIN OF TETRAZOLIUM REDUCTASE OF ESCHERICHIA COLI

Abstract

Streptomycin partially inhibited the menadione-mediated NADH2: triphenyltetrazolium chloride oxidoreductase (menadione reductase) of Escherichia coli at concentrations as low as 10−5 M. One molecule of streptomycin interacted with three sensitive sites on the enzyme. Streptidine reacted with a single sensitive site. Streptomycin inhibited the system in competition with the dye (Ki, 1.5 × 10−3 M) but did not inhibit the binding of FAD to the apoenzyme.