Fig. 1
From: Metabolite toxicity determines the pace of molecular evolution within microbial populations
The denitrification pathway of P. stutzeri. Nitrate is first reduced to nitrite in the cytoplasm. Nitrite is then actively transported to the periplasmic space where it is further reduced through several intermediates to dinitrogen gas. The consequence is that nitrite accumulates in the periplasm. Enzymes: Nar, nitrate reductase; Nir, nitrite reductase; Nor, nitric oxide reductase; Nos, nitrous oxide reductase