Inhibitory anti-CYP3A4 peptide antibody: mapping of inhibitory epitope and specificity toward other CYP3A isoforms.
Drug Metab Dispos
; 27(2): 167-72, 1999 Feb.
Article
en En
| MEDLINE
| ID: mdl-9929498
ABSTRACT
An antipeptide antibody has been produced that recognizes CYP3A4 and exhibits greater than 90-95% inhibition on CYP3A4-mediated reactions [Wang RW and Lu AYH (1997) Drug Metab Dispos 25762-767]. The inhibitory epitope of the 21-amino acid peptide, corresponding to residues 253 to 273 of CYP3A4, has been identified to reside in a 7-amino acid sequence (LEDTQKH residues 261-267 of CYP3A4). This conclusion was based on the reversal of antibody inhibition of testosterone 6beta-hydroxylation when peptides with overlapping sequence in this region were preincubated with the antibody. In immunoblotting analysis, this antibody did not recognize CYP3A5 or CYP3A7 in microsomes prepared from baculovirus-infected cells containing these two expressed isoforms. In addition, the antipeptide antibody did not inhibit testosterone 6beta-hydroxylation or midazolam 1'- and 4-hydroxylation in microsomes containing expressed CYP3A5 and CYP3A7. Because the corresponding sequence in CYP3A5 (LNDKQKH) and CYP3A7 (LKETQKH) differs from CYP3A4 by only two amino acids, six peptides with either one or two amino acid changes were used to determine which amino acid is essential for antibody-antigen interaction. Our data indicate that Glu, Asp, and Thr in the 7-amino acid sequence of CYP3A4 are critical determinants of selectivity among CYP3A isoforms.
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Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Hidrocarburo de Aril Hidroxilasas
/
Mapeo Epitopo
/
Sistema Enzimático del Citocromo P-450
/
Oxigenasas de Función Mixta
/
Anticuerpos
Límite:
Humans
Idioma:
En
Revista:
Drug Metab Dispos
Asunto de la revista:
FARMACOLOGIA
Año:
1999
Tipo del documento:
Article
País de afiliación:
Estados Unidos