NADPH is a critical cofactor supporting numerous biochemical reactions. In ADME-Tox studies, NAD(P)H regeneration is strongly recommended when using drug metabolizing enzymes (ex. Cytochrome P450 (CYP), Flavin-containing MonoOxygenases (FMO)), Recombinant CYPs (incl. bactosomes) or cellular fractions (Microsomes, S9).  Currently, the most simple and cost-effective way to regenerate the NAD(P)H in situ and enzymatically is to use the commercially-available RapidStart™ NADPH Regenerating System (Xenotech-Sekisui).

RapidStart uses an enzymatic reaction that changes NADP to NADPH, which is then oxidized by CYPs back to NADP, and the cycle continues…

Recombinant CYPs are commonly used in ADME-Tox studies as in vitro tools, mostly for reaction phenotyping, enzyme inhibition screening, clearance and metabolite ID.

“Research has shown that rCYPs expressed in E. coli (Bactosomes) showed greater enzymatic activity compared with the equivalent enzymes expressed in insect cells (Supersomes). Similarly, most Bactosomes show greater turnover numbers when compared with the equivalent Supersomes. These results demonstrate that human rCYPs expressed in E. coli are frequently more active than the corresponding rCYPs expressed in insect cells» says Michael Voice from CYPEX.

If you are looking for enzymatic in vitro tools for drug metabolism, reaction phenotyping, metabolite generation, using pig as model, you may find these newly released Pig Bactosomes from Cypex of interest.

Bactosomes are recombinant enzymes expressed in E. coli with a patented expression system that enables expression of drug metabolising enzymes without the need for large modifications to be made to the proteins. They demonstrate excellent batch-to-batch consistency and robust activity levels. Each batch is characterized for linearity with time and CYP concentration, Km and Vmax.