Skip Navigation

This Article
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Add to My Personal Archive
Right arrow Download to citation manager
Right arrow Request Permissions
Google Scholar
Right arrow Articles by Hokama, Y.
Right arrow Articles by Yoshimura, H.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Hokama, Y.
Right arrow Articles by Yoshimura, H.
Social Bookmarking
Add to CiteULike   Add to Connotea   Add to Del.icio.us  
What's this?

J. Biochem, 1988, Vol. 104, No. 3 355-361
© 1988 Japanese Biochemical Society

research-article

Purification and Characterization of Two Forms of Chicken Liver Cytochrome P-450 Induced by 3,4,5,3',4'-Pentachlorobiphenyl1

Yumiko Hokama, Nobuyuki Koga and Hidetoshi Yoshimura2

Faculty of Pharmaceutical Sciences, Kyushu University Higashi-ku, Fukuoka, Fukuoka 812

2To whom reprint requests should be sent

3,4,5,3',4'-Pentachlorobiphenyl (PenCB), one of the most potent 3-methyleholanthrene (MC)-type inducers of hepatic enzymes in animals, caused a remarkable induction of liver microsomal monooxygenases, particularly 7-ethoxyresorufin (7-ER) O-deethylase, benzo(a)pyrene (BP) 3-hydroxylase, and testosterone 16{alpha}-hydroxylase in chickens, but not NADPH-cytochrome c(P-450) reductase and cytochrome b5. Two forms of cytochrome P-450 (P-450) in liver microsomes of PenCB-treated chickens were purified and characterized. The absorption maxima of the CO-reduced difference spectra of both enzymes (chicken P-448 L and chicken P-448 H) were at 448 nm. From the oxidized form of their absolute spectra, chicken P-448 L was a low-spin form and chicken P-448 H was a high-spin form. They had molecular masses of 56 and 54 kDa, respectively. In a reconstituted system, 7-ER O-deethylation, BP 3-hydroxylation, and testosterone 16{alpha}-hydroxylation were catalyzed at high rates by chicken P-448 L but not by chicken P-448 H. Chicken P-448 L also catalyzed N-demethylation of aminopyrine, benzphetamine, and ethylmorphine with relatively low activity. On the other hand, chicken P-448 H functioned only in catalyzing estradiol 2-hydroxylation. These results were supported by an inhibition study of microsomal monooxygenases using an antibody against each enzyme. Immunochemical studies revealed that the enzymes differ from each other but are both inducible by PenCB-treatment. Chicken P-448 L and chicken P-448 H respectively comprise about 82 and 7% of the total P-450 content in chicken liver microsomes.

1This work was supported in part by a Grant-in-Aid for Scientific Research from the Ministry of Health and Welfare of Japan.


Add to CiteULike CiteULike   Add to Connotea Connotea   Add to Del.icio.us Del.icio.us    What's this?




Disclaimer: Please note that abstracts for content published before 1996 were created through digital scanning and may therefore not exactly replicate the text of the original print issues. All efforts have been made to ensure accuracy, but the Publisher will not be held responsible for any remaining inaccuracies. If you require any further clarification, please contact our Customer Services Department.