Cypex CYP3A4 QC
Activity: Testosterone 6b-hydroxylase
buffer: 0.1 M potassium phosphate pH 7.4, 5 mM MgCl2
Incubation volume: 200 µl
Stop reagent: 1 M hydrochloric acid (25 µl)
Internal standard: 4-androstene-3,17-dione (10 µl of 10
Column: Hypersil ODS (5 µm) 250 x
Mobile phase: 0.05% orthophosphoric acid/methanol 44/56 (v/v)
Flow rate: 1.0 ml/min
Run time: 18.5 min
Injection volume: 50 µl
Detection: UV, l
= 240 nm
of phosphate concentration on testosterone turnover by CYP3A4R and
turnover by CYP3A4 is sensitive to the concentration of phosphate in
assays were carried out at 200 µM testosterone at a P450
concentration of 2.5 pmol per 200 µl.
The length of time for which product formation is linear is also
affected by phosphate concentration.
Details of a plate reader assay for CYP3A4 activity using 7BQ can be found here.
under licence from BTG International Ltd (AU730155, EP0914446,
US6566108 and other patents pending).
United States Patent Nos. 5,420,027 or 5,240,831, Canada Patent No.
2100245 and other patents pending.