Oxidation–reduction potentials of molybdenum and iron–sulphur centres in nitrate reductase from Escherichia coli

Abstract

The potentials of the couples Mo(IV)–(Mo(V) and Mo(V)–Mo(VI) in nitrate reductase from Escherichia coli K12 were measured as + 180 mV and + 220 mV respectively at pH 7.14. The potentials associated with two other e.p.r. signals, believed to be due to iron–sulphur centres, were measured as + 50 mV and + 80 mV.