Mouse liver phenobarbital-inducible P450 system: Purification, characterization, and differential inducibility of four cytochrome P450 isozymes from the D2 mouse

Honkakoski, Paavo and Lang, Matti A. (1989) Mouse liver phenobarbital-inducible P450 system: Purification, characterization, and differential inducibility of four cytochrome P450 isozymes from the D2 mouse. Archives of Biochemistry and Biophysics, 273 1: 42-57. doi:10.1016/0003-9861(89)90160-4


Author Honkakoski, Paavo
Lang, Matti A.
Title Mouse liver phenobarbital-inducible P450 system: Purification, characterization, and differential inducibility of four cytochrome P450 isozymes from the D2 mouse
Journal name Archives of Biochemistry and Biophysics   Check publisher's open access policy
ISSN 0003-9861
1096-0384
Publication date 1989-08
Sub-type Article (original research)
DOI 10.1016/0003-9861(89)90160-4
Volume 273
Issue 1
Start page 42
End page 57
Total pages 16
Place of publication Maryland Heights, MO, United States
Publisher Academic Press
Language eng
Abstract Three novel cytochrome P450 isozymes were purified from phenobarbital (PB)-treated D2 mouse liver microsomes and compared to the previously characterized coumarin 7-hydroxylase, P450Coh. The molecular masses were 56.5, 55, 51, and 49.5 kDa, and the peaks of the reduced CO complexes were at 450, 447.5, 451.5 and 449 nm for P450PBI, P450PBII, P450PBIII, and P450Coh, respectively. The NH2-terminal sequences suggest that these isozymes belong to the P450 gene subfamilies 2B, 1A, 2C, and 2A, respectively. On the basis of reconstituted activities and microsomal immunoinhibition studies, P450Coh was the sole catalyst of coumarin 7-hydroxylation. P450PBI was the major isozyme catalyzing the high K(m) 7-pentoxyresorufin O-dealkylation. This reaction was also mediated at a slower rate by the low K(m) isozyme, P450PBII. P450PBIII contributed significantly to the microsomal O-deethylation of the 7-ethoxyresorufin and N-demethylation of benzphetamine. Western blotting and dot immunobinding analyses of microsomes showed that the induction patterns of the isozymes were different. PB and TCPO-BOP induced all isozymes variably: P450PBI (19- and 31-fold), P450PBII (2- and 3-fold), P450PBIII (9- and 4-fold), and P450Coh (about 2-fold). Pyrazole induced only P450Coh, while all other isozymes were decreased by 30 to 60%. The changes in the microsomal amounts of these isozymes correlated generally well with the variation in the immunoinhibitable enzyme activities. On the basis of the structural and catalytic properties, immunochemical characteristics, and induction profiles, all three isozymes were different from each other and from the previously characterized P450Coh. This mouse PB-inducible P450 model may be valuable in further studies on the induction mechanisms of PB and TCPOBOP.
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Non-UQ

Document type: Journal Article
Sub-type: Article (original research)
Collection: National Research Centre for Environmental Toxicology Publications
 
Versions
Version Filter Type
Citation counts: TR Web of Science Citation Count  Cited 72 times in Thomson Reuters Web of Science Article | Citations
Scopus Citation Count Cited 62 times in Scopus Article | Citations
Google Scholar Search Google Scholar
Created: Mon, 30 Nov 2009, 15:02:44 EST