The Inducible Trimethylamine N-oxide Reductase of Escherichia Coli K12: Its Localization and Inducers

Biochim Biophys Acta. 1989 Nov 30;999(2):208-16. doi: 10.1016/0167-4838(89)90220-3.


We used an anti-trimethylamine-N-oxide reductase (EC serum and different immunological techniques (Ouchterlony, rocket immunoelectrophoresis, immunoblotting) to show that dimethylsulphoxide (DMSO), tetrahydrothiophene 1-oxide (THTO) and pyridine N-oxide (PNO) were effective inducers of the inducible form of trimethylamine N-oxide reductase. We confirmed this genetically and biochemically using a strain in which phage MudII 1734 carrying lacZ was inserted into torA, the structural gene for inducible trimethylamine-N-oxide reductase. By subcellular fractionation and quantitation with rocket immunoelectrophoresis, we showed that the enzyme was principally localized in the periplasmic fraction. Constitutive trimethylamine-N-oxide reductase was localized in the membrane fraction and, like the inducible enzyme showed a broad specificity with respect to various compounds such as DMSO, THTO and PNO. Apart from their immunological properties, the two enzymes could be clearly differentiated by their temperature stability.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Anaerobiosis
  • Dimethyl Sulfoxide / pharmacology
  • Enzyme Induction
  • Escherichia coli / drug effects
  • Escherichia coli / enzymology*
  • Escherichia coli / genetics
  • Genotype
  • Immune Sera
  • Immunodiffusion
  • Immunoelectrophoresis
  • Kinetics
  • Macromolecular Substances
  • Methylamines / pharmacology
  • NADH, NADPH Oxidoreductases / biosynthesis*
  • NADH, NADPH Oxidoreductases / isolation & purification
  • NADH, NADPH Oxidoreductases / metabolism
  • Oxidoreductases Acting on CH-NH Group Donors
  • Pyridines / pharmacology


  • Immune Sera
  • Macromolecular Substances
  • Methylamines
  • Pyridines
  • pyridine N-oxide
  • methylamine dehydrogenase
  • Oxidoreductases Acting on CH-NH Group Donors
  • NADH, NADPH Oxidoreductases
  • trimethyloxamine
  • Dimethyl Sulfoxide