title: Resolution of multiple P-450 forms: separation of aryl hydrocarbon hydroxylase and aminopyrine N-demethylase-associated P-450 isoenzymes by chromatofocusing.
abstract: Chromatofocusing between pH 7.4 and 5.0 was introduced as a final step for the resolution of multiple forms of cytochrome P-450 from control, phenobarbital and 3-methylcholanthrene-pretreated rat liver microsomal fractions. Altogether, chromatofocusing produced 21 P-450-containing pools, which differed from each other with respect to substrate specificity, spectral maximum and elution pH. Aryl hydrocarbon (benzo(a)pyrene) hydroxylase (AHH) activity was concentrated into low pI pools in all animal groups. 7-Ethoxycoumarin O-deethylase (ECOD) activity comigrated with AHH activity throughout the purification procedure. Aminopyrine N-demethylase (APND) activity was spread into several pools with forms of both low and high pI proteins.
mesh_terms: D000633:Aminopyrine N-Demethylase / Q000302:isolation & purification*; D000818:Animals; D001189:Aryl Hydrocarbon Hydroxylases / Q000302:isolation & purification*; D002845:Chromatography; D003577:Cytochrome P-450 Enzyme System / Q000302:isolation & purification*; D004591:Electrophoresis, Polyacrylamide Gel; D006863:Hydrogen-Ion Concentration; D007526:Isoelectric Point; D007527:Isoenzymes / Q000302:isolation & purification*; D008297:Male; D008748:Methylcholanthrene / Q000494:pharmacology; D008862:Microsomes, Liver / Q000187:drug effects / Q000201:enzymology*; D008970:Molecular Weight; D010634:Phenobarbital / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains
chemical_list: D007527:Isoenzymes; D008748:Methylcholanthrene; D003577:Cytochrome P-450 Enzyme System; D001189:Aryl Hydrocarbon Hydroxylases; D000633:Aminopyrine N-Demethylase; D010634:Phenobarbital