The action of sodium azide on cellular respiration and on some catalytic oxidation reactions

Abstract

Acid methemoglobin reacts with azide to form a red compound with absorption bands at 575 and 542.5 m[mu], one molecule of NaN3 combining per atom of Fe of methemoglobin. NaN3 is not known to combine with other derivatives of Hb. In concns. of 0.001-0.003 M, it completely inhibits liver catalase, inhibits yeast catalase by 94%, indophenol oxidase by 80-95%, peroxidase by 70%, behaving in these respects like KCN and H2S. In acid solution, it inhibits catechol oxidase, the oxidation of reduced cytochrome in living yeast, the resp. of yeast cells; at pH 7.5 or over, no inhibition of these processes by azide occurs. It also inhibits the catalytic oxidation of cysteine by hematin, but since it does not combine with hematin, the inactiva-tion, like that of [alpha][alpha]-dipyridyl, is attributed to inactiva-tion of some iron derivation of hematin.