Observation of Two Different Chromophores in the Resting State of Monoamine Oxidase B by Fluorescence Spectroscopy

Jonathan C.G. Woo, Richard B. Silverman*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

12 Scopus citations

Abstract

Catalytically active monoamine oxidase (MAO) is believed to exist as a dimer with each subunit containing a covalently attached flavin cofactor. Fluorescence spectroscopy performed on the resting state enzyme resulted in two separate fluorescence emissions at 480 nm and 530 nm with excitation maxima at λex = 412 nm and λex = 450 nm, respectively. Inactivation of MAO with pargyline resulted in concomitant loss of the absorbance at 450 nm without change in the 412 nm absorption; there also was a decrease in the emission intensity at 530 nm, while the emission at 480 nm remained unchanged. The 480 nm emission decreased and the 530 nm emission intensity increased, when the enzyme was heat denatured in the presence of NaDodSO4. From these results, it is clear that there are two different chromophores present in the resting state enzyme; the 530 nm chromophore is consistent with an oxidized flavin, while the 480 nm chromophore could be a flavin semiquinone.

Original languageEnglish (US)
Pages (from-to)1574-1578
Number of pages5
JournalBiochemical and Biophysical Research Communications
Volume202
Issue number3
DOIs
StatePublished - Aug 15 1994

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Molecular Biology
  • Cell Biology

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