RT Journal Article
SR Electronic
T1 Disparity in Holoprotein/Apoprotein Ratios of Different Standards Used for Immunoquantification of Hepatic Cytochrome P450 Enzymes
JF Drug Metabolism and Disposition
JO Drug Metab Dispos
FD American Society for Pharmacology and Experimental Therapeutics
SP 1733
OP 1736
DO 10.1124/dmd.107.015743
VO 35
IS 10
A1 H. F. Perrett
A1 Z. E. Barter
A1 B. C. Jones
A1 H. Yamazaki
A1 G. T. Tucker
A1 A. Rostami-Hodjegan
YR 2007
UL http://dmd.aspetjournals.org/content/35/10/1733.abstract
AB An analysis of reported hepatic abundances of CYP3A4 and 3A5 indicated that values determined by immunoquantification using commercially available, unpurified recombinant enzymes as standards are significantly lower than those determined using purified enzymes or human liver microsomes characterized with lysosomal peptides (CYP3A4: mean 45 versus 121 pmol/mg protein, p < 0.01; CYP3A5: mean 28 versus 83 pmol/mg protein, p < 0.05). When immunoquantifying cytochromes P450 (P450s), it is assumed that the holoprotein (holo)/apoprotein ratio is the same in the samples and the standard. Estimates of holo/apoprotein ratios from data reported for a range of P450s purified from human liver and non-commercial recombinant systems indicated less than complete and variable heme coupling dependent on enzyme and system. The American Society for Pharmacology and Experimental Therapeutics