Publication detail

Modulation of human cytochrome P450 1A1-mediated oxidation of benzo[a]pyrene by NADPH:cytochrome P450 oxidoreductase and cytochrome b(5)

INDRA, R. MOSEROVÁ, M. KROFTOVÁ, N. ŠULC, M. MARTÍNKOVÁ, M. ADAM, V. ECKSCHLAGER, T. KIZEK, R. ARLT, V.M. STIBOROVÁ, M.

Original Title

Modulation of human cytochrome P450 1A1-mediated oxidation of benzo[a]pyrene by NADPH:cytochrome P450 oxidoreductase and cytochrome b(5)

Type

journal article in Web of Science

Language

English

Original Abstract

OBJECTIVES: Cytochrome P450 (CYP) 1A1 located in the membrane of endoplasmic reticulum is the most important enzyme in both activation and detoxification of carcinogenic benzo[a]pyrene (BaP), in combination with microsomal epoxide hydrolase (mEH). However, it is still not clearly explained how the electron transfer is mediated by NADPH: CYP oxidoreductase (POR), another component of the microsomal enzymatic system, on CYP1A1 during BaP oxidation, and whether microsomal cytochrome b(5) might influence this electron transfer. METHODS: High performance liquid chromatography (HPLC) was employed for separation of BaP metabolites formed by enzymatic systems containing human CYP1A1. RESULTS: Human CYP1A1 expressed with POR in eukaryotic and prokaryotic expression cellular systems, in microsomes of insect cells (Supersomes (TM)) and in a membrane fraction of Escherichia coli, respectively, and these enzyme systems reconstituted with purified cytochrome b5 were utilized to study BaP oxidation. Human CYP1A1 expressed in Supersomes (TM) oxidized BaP to seven metabolites [7,8-and 9,10-dihydrodiols, 1,6-dione, 3,6-dione, 3- and 9-phenols, and a metabolite with unknown structure (Mx)], whereas this enzyme expressed in membranes of E. coli formed only the metabolites 1,6- and 3,6-diones, 3- and 9-phenols, and Mx. Addition of cytochrome b(5) to CYP1A1 expressed in the eukaryotic system led to a more than 2-fold increase in BaP metabolism, but had essentially no effect on BaP oxidation by CYP1A1 expressed in E. coli. CONCLUSION: The effect of cytochrome b(5) on CYP1A1 conformation and the electron transfer to this enzyme may contribute to the cytochrome b(5)-mediated stimulation of BaP oxidation.

Keywords

benzo[a]pyrene; human carcinogen; metabolism; human and rat cytochrome P450 1A1; NADPH:cytochrome P450 oxidoreductase; cytochrome b(5)

Authors

INDRA, R.; MOSEROVÁ, M.; KROFTOVÁ, N.; ŠULC, M.; MARTÍNKOVÁ, M.; ADAM, V.; ECKSCHLAGER, T.; KIZEK, R.; ARLT, V.M.; STIBOROVÁ, M.

Released

1. 1. 2014

ISBN

0172-780X

Periodical

NEUROENDOCRINOLOGY LETTERS

Year of study

35

Number

2

State

Kingdom of Sweden

Pages from

105

Pages to

113

Pages count

9

BibTex

@article{BUT145262,
  author="INDRA, R. and MOSEROVÁ, M. and KROFTOVÁ, N. and ŠULC, M. and MARTÍNKOVÁ, M. and ADAM, V. and ECKSCHLAGER, T. and KIZEK, R. and ARLT, V.M. and STIBOROVÁ, M.",
  title="Modulation of human cytochrome P450 1A1-mediated oxidation of benzo[a]pyrene by NADPH:cytochrome P450 oxidoreductase and cytochrome b(5)",
  journal="NEUROENDOCRINOLOGY LETTERS",
  year="2014",
  volume="35",
  number="2",
  pages="105--113",
  issn="0172-780X"
}