Abstract
Nitrous oxide reductase from Wolinella succinogenes was purified very nearly to homogeneity. The enzyme was found to be dimeric, with M,=162,000 and subunit M, =88,000,and to contain three copper atoms and one iron atom (as cytochrome c) per subunit. The oxidized enzyme exhibited absorption bands at 410 and 528 nm, and the dithionite-reduced enzyme, at 416, 520,and550nm. The isoelectric point was 8.6; specific activity was at 25 C and pH 7.1, 1M60molX min” X mg“; and K , was 7.5 MM NzO under the same conditions. a-Chymotrypsin cleaved the enzyme into cytochrome c-depleted dimerswith anaverage M, = mg“; and K , was 7.5 MM NzO under the same conditions.