The effect of oxygen on Chromatographie behavior and properties of nitrous oxide reductase

Abstract

Nitrous oxide reductase, a high‐ M r copper protein, was purified under anaerobic conditions to yield a spectroscopically new species with 3–5‐fold increased catalytic activity over the ‘pink’ form of the enzyme obtained thus far. The preparation was homogeneous by chromatographic and electrophoretic criteria and reduced N 2 O to N 2 . On aerobic gel filtration of a crude extract, the enzymatic activity was slightly shifted from the Cu‐protein towards an apparent lower M r . This effect was not observed under anaerobic conditions, nor was it observed with the purified enzyme on either aerobic or anaerobic chromatography. In crude extracts, oxygen appears to convert the Cu‐protein to a lower activity form at the leading edge of a migrating chromatographic zone.