Direct continuous fluorometric assay for monoamine oxidase B

Joseph J.P. Zhou, Boyu Zhong, Richard B. Silverman*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

28 Scopus citations


The first direct and continuous fluorometric assay for monoamine oxidase B (MAO B) has been developed. E-2,5-Dimethoxycinnamylamine hydrochloride was designed and synthesized and was found to be an excellent substrate for MAO B (K(m) = 218 μM, K(cat) = 435 min-1). This compound has an intense purple fluorescence when irradiated at λ(ex) = 343 nm (λ(em) = 393 nm) in Tris buffer, pH 9.0, or sodium phosphate buffer, pH 7.2, but under the same conditions, the corresponding aidehyde, the product of the MAO-catalyzed oxidation of E-,5-dimethoxycinnamylamine hydrochloride, does not fluoresce. The activity of MAO B, therefore, can be determined efficiently and rapidly by continuously following the decrease in fluorescence at 393 nm at enzyme concentrations as low as 100 nM. The change in fluorescence is linear up to a substrate concentration of 500 μM.

Original languageEnglish (US)
Pages (from-to)9-12
Number of pages4
JournalAnalytical Biochemistry
Issue number1
StatePublished - Feb 1 1996

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Molecular Biology
  • Cell Biology


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