. "Catalysis of the reaction: NH3 + 2 H2O + 6 ferricytochrome c = nitrite + 6 ferrocytochrome c + 7 H+." . . "nitrite reductase (cytochrome, ammonia-forming)" . "nitrite reductase (cytochrome, ammonia-forming) activity" . "ammonia:ferricytochrome-c oxidoreductase activity" . "cytochrome c nitrite reductase activity" . "cytochrome c552 activity" . "multiheme nitrite reductase activity" . . .