Figure 20

Fig. 20: Optical micro-spectrophotometer spectra of cryo-cooled (100K) nitrite-reductase crystals. Features at 500-560 nm are characteristic of the c-heme, whereas features at 620-670 nm are characteristic of the d₁-heme. The green spectrum corresponds to the c-ox/d₁-ox state, the yellow spectrum corresponds to the c-red/d₁-ox state, and the red spectrum corresponds to the c-red/d₁-red state.