Purification and Characterization of Nitrite-oxidizing Enzyme from Heterotrophic Bacillus badius I-73, with Special Concern to Catalase

Abstract

  Nitrite-oxidizing enzyme I (NiOx I) was purified from a heterotrophic bacterium, Bacillus badius I-73. The enzyme was a homotetramer of a heme-containing peptide, and was similar to catalases from various sources in its N-terminal amino acid sequence. The purified enzyme also catalyzed H₂O₂ degradation. The nitrite oxidation reaction required ascorbic acid and oxygen. Successive H₂O₂ feeding could be substituted for ascorbic acid. These indicated that NiOx I is a catalase and nitrite was oxidized by a peroxidase-like reaction.