Quinoline oxidoreductase from Pseudomonas putida 86: an improved purification procedure and electron paramagnetic resonance spectroscopy

Biochemistry. 1993 Nov 30;32(47):12928-34. doi: 10.1021/bi00210a047.


Quinoline oxidoreductase, an iron-sulfur molybdenum flavoprotein containing flavin adenine dinucleotide and molybdopterin cytosine dinucleotide, was purified from Pseudomonas putida 86 to homogeneity. The various electron-transfer centers of the purified enzyme were examined by electron paramagnetic resonance spectroscopy. Quinoline deuterated at position 2 was prepared by deuterodecarboxylation of 2-quinolinecarboxylic acid. Quinoline added to the enzyme elicited the Mo(V) "rapid" type Q signal arising from the complex of enzyme and substrate, whereas in oxidized quinoline oxidoreductase a Mo(V) "resting" signal was observed. EPR spectroscopy at helium temperatures below 70 K revealed the existence of two types of iron-sulfur centers, Fe-S I and Fe-S II. An organic free radical appeared upon reduction with sodium dithionite. Inactivation of the enzyme by cyanide led to the inactive desulfo quinoline oxidoreductase, which yielded another Mo(V) signal designated "slow" type Q upon reduction with dithionite. Desulfo quinoline oxidoreductase was partially reactivated by incubation with sulfide.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cyanides / pharmacology
  • Electron Spin Resonance Spectroscopy
  • Enzyme Reactivators / pharmacology
  • Free Radicals
  • Iron-Sulfur Proteins / chemistry*
  • Iron-Sulfur Proteins / drug effects
  • Iron-Sulfur Proteins / isolation & purification
  • Molybdenum / chemistry
  • Oxidation-Reduction
  • Oxidoreductases / chemistry*
  • Oxidoreductases / drug effects
  • Oxidoreductases / isolation & purification
  • Oxidoreductases Acting on CH-CH Group Donors*
  • Pseudomonas putida / enzymology*
  • Pseudomonas putida / growth & development
  • Sulfides / pharmacology


  • Cyanides
  • Enzyme Reactivators
  • Free Radicals
  • Iron-Sulfur Proteins
  • Sulfides
  • Molybdenum
  • Oxidoreductases
  • Oxidoreductases Acting on CH-CH Group Donors
  • quinoline 2-oxidoreductase
  • sodium sulfide