The two terminal oxidases of the aerobic respiratory chain of Escherichia coli each yield water and not peroxide as a final product

Kimberly Carter Minghetti, Robert B. Gennis

Research output: Contribution to journalArticle

Abstract

The aerobic respiratory chain of Escherichia coli contains two terminal oxidases, the cytochrome d complex and the cytochrome o complex. Each of these enzymes catalyzes the oxidation of ubiquinol-8 within the cytoplasmic membrane and reduces molecular oxygen. The purpose of this work is to experimentally verify that each of the terminal oxidases yields water as a product with no significant amount of hydrogen peroxide. This was accomplished by preparing membranes which were washed so as to eliminate membrane-associated catalase and peroxidase activities. The NADH oxidase activity of the membrane-bound respiratory chain was measured by monitoring the rates of both NADH and oxygen utilization. This was performed using membranes from strains in which either cytochrome o or cytochrome d were absent. Results using each strain showed two NADH utilized per oxygen, indicating a four-electron reduction of oxygen to water.

Original languageEnglish (US)
Pages (from-to)243-248
Number of pages6
JournalBiochemical and Biophysical Research Communications
Volume155
Issue number1
DOIs
StatePublished - Aug 30 1988

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Molecular Biology
  • Cell Biology

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