Purification of hydroxylamine oxidase from Thiosphaera pantotropha. Identification of electron acceptors that couple heterotrophic nitrification to aerobic denitrification

FEBS Lett. 1993 Dec 6;335(2):246-50. doi: 10.1016/0014-5793(93)80739-h.

Abstract

Thiosphaera pantotropha, a Gram-negative heterotrophic nitrifying bacterium, expresses a soluble 20 kDa monomeric periplasmic hydroxylamine oxidase that differs markedly from the hydroxylamine oxidase found in autotrophic bacteria. This enzyme can use the periplasmic redox proteins, cytochrome c551 and pseudoazurin as electron acceptors, both of which can also donate electrons to denitrification enzymes. A model of electron transfer is proposed, that suggests a coupling of nitrification and provides a mechanism by which nitrification can play a role in dissipating reductant.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Electron Transport / physiology
  • Gram-Negative Chemolithotrophic Bacteria / enzymology*
  • Nitrogen / metabolism*
  • Oxidoreductases / isolation & purification*

Substances

  • Oxidoreductases
  • hydroxylamine dehydrogenase
  • Nitrogen