A direct fluorometric assay of benzo[a]pyrene hydroxylase

Chung S. Yang, Louis P. Kicha

Research output: Contribution to journalArticlepeer-review

47 Scopus citations

Abstract

The fluorescence of benzo[a]pyrene is greatly enhanced upon binding to microsomes. The excitation and emission maxima are 387 and 407 nm, respectively. At this wavelength setting, the fluorescence of the benzo[a]pyrene metabolites is very low. Therefore, the oxidative metabolism of benzo[a]pyrene can be assayed by following the NADPH-dependent deerease in fluorescence with a recording spectrofluorometer. Under optimal conditions, the decrease in fluorescence follows first-order kinetics and the rate of the reaction is proportional to the amount of microsomes in the assay system. The rate of metabolism of some benzo[a]pyrene derivatives can also be assayed by a similar method. In comparison with the commonly used benzo[a]pyrene hydroxylase assay, this direct fluorometric assay employs lower substrate concentrations (0.1-2.0 μm benzo[a]pyrene) and reveals a larger difference between the activities of control and 3-methylcholanthrene-induced microsomes. The method is also easier and allows the entire course of the reaction to be measured.

Original languageEnglish (US)
Pages (from-to)154-163
Number of pages10
JournalAnalytical Biochemistry
Volume84
Issue number1
DOIs
StatePublished - Jan 1978

All Science Journal Classification (ASJC) codes

  • Biophysics
  • Biochemistry
  • Molecular Biology
  • Cell Biology

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