Mechanism of nitrite inhibition of cellular respiration inPseudomonas aeruginosa

One of the principal mechanisms of nitrite inhibition of cellular respiration has been considered to be the interference with the action of iron-containing enzymes. In procaryotic systems, the effect of nitrite on cellular metabolism remains unclear. This study provides evidence which shows a direct inhibition by a low concentration of nitrite on a highly purified oxidase inPseudomonas aeruginosa. The inhibition pattern was observed and was consistent at cellular, electron-transport membranous, and enzymic (oxidase) levels. This implies that the mechanism of nitrite inhibition on bacterial respiration is due to a direct inhibition at the terminal site of oxygen reduction. The uncompetitive inhibition pattern shown by nitrite strongly suggested a mechanism quite different from those of classic cytochrome oxidase inhibitors such as cyanide, azide, and carbon monoxide.