Cyanate is transported by the nitrate permease in Azotobacter chroococcum

Abstract Azotobacter chroococcum cells exhibiting the capacity to take up nitrate actively could transport ¹⁴C]cyanate. This activity was dependent on the nitrogen source present in the culture medium, ammonium acting as a repressor and nitrate as an inducer. The uptake of cyanate required metabolic energy and was absent from A. Chroococcum TR1, a mutant strain lacking the nitrate transport system, but was present at wild-type levels in A. chroococcum E4, a mutant strain deficient in nitrate reductase. These results show that cyanate is transported by the nitrate permease in A. chroococcum and therefore ¹⁴C]cyanate may be useful as a nitrate analogue for studies on nitrate transport.