当前位置： SCI文献检索 > JOURNAL OF PHARMACOLOGICAL AND TOXICOLOGICAL METHODS期刊下所有文献 > Functional properties and substrate characterization of human CYP26A1, CYP26B1, and CYP26C1 expressed by recombinant baculovirus in insect cells.

Functional properties and substrate characterization of human CYP26A1, CYP26B1, and CYP26C1 expressed by recombinant baculovirus in insect cells.

Abstract：

INTRODUCTION:The cytochrome P450 CYP26 family of retinoic acid (RA) metabolizing enzymes, comprising CYP26A1, CYP26B1, and CYP26C1 is critical for establishing patterns of RA distribution during embryonic development and retinoid homeostasis in the adult. All three members of this family can metabolize all trans-RA. CYP26C1 has also been shown to efficiently metabolize the 9-cis isomer of RA. METHODS:We have co-expressed each of the CYP26 enzymes along with the NADPH-cytochrome P450 oxidoreductase using a baculovirus/Sf9 insect cell expression system to determine the enzymatic activities of these enzymes in cell free preparations and have established an in vitro binding assay to permit comparison of binding affinities of the three CYP26 enzymes. RESULTS:We demonstrated that the expressed enzymes can efficiently coordinate heme, as verified by spectral-difference analysis. All CYP26s efficiently metabolized all-trans-RA to polar aqueous-soluble metabolites, and in competition experiments exhibited IC(50) values of 16, 27, and 15nM for CYP26A1, B1, and C1 respectively for all-trans-RA. Furthermore, this metabolism was blocked with the CYP inhibitor ketoconazole. CYP26C1 metabolism of all trans-RA could also be effectively competed with 9-cis RA, with IC(50) of 62nM, and was sensitive to ketoconazole inhibition. DISCUSSION:CYP26 enzymes are functionally expressed in microsomal fractions of insect cells and stably bind radiolabeled RA isomers with affinities respecting their substrate specificities. We demonstrated that compared to CYP26A and CYP26B, only CYP26C1 was able to bind with high affinity to 9-cis-RA. These assays will be useful for the screening of synthetic substrates and inhibitors of CYP26 enzymes and may be applicable to other cytochrome P450s and their respective substrates.

journal_name

J Pharmacol Toxicol Methods

journal_title

Journal of pharmacological and toxicological methods

authors

Helvig C,Taimi M,Cameron D,Jones G,Petkovich M

doi

10.1016/j.vascn.2011.08.005

subject

Has Abstract

pub_date

2011-11-01 00:00:00

pages

258-63

issue

eissn

1056-8719

issn

1873-488X

pii

S1056-8719(11)00280-2

journal_volume

pub_type

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Functional properties and substrate characterization of human CYP26A1, CYP26B1, and CYP26C1 expressed by recombinant baculovirus in insect cells.