Metabolic pathways, substrates, metabolites, and LC/MS-MS parameters for the quantification of the DME activities of cryopreserved human enterocytes
Tolbutamide was used as an internal standard with the mass transition monitoring at m/z 271.2 to 91.3 and m/z269.1 to 105.9 for positive mode and negative mode, respectively.
| Metabolic Pathway | Pathway-Selective Substrate (µM) | Marker Metabolite | Ion Mode Application | Mass Transition Monitoring |
|---|---|---|---|---|
| CYP1A2 | Phenacetin (100) | Acetaminophen | Positive | m/z 152.1 to 109.9 |
| CYP2A6 | Coumarin (50) | 7-Hydroxycoumarin | Negative | m/z 161.0 to 132.9 |
| CYP2B6 | Bupropion (500) | Hydroxybupropion | Positive | m/z 250.1 to 130.1 |
| CYP2C8 | Paclitaxel (20) | 6α-Hydroxypaclitaxel | Positive | m/z 870.4 to 525.2 |
| CYP2C9 | Diclofenac (25) | 4-Hydroxydiclofenac | Negative | m/z 309.8 to 265.9 |
| CYP2C19 | S-Mephenytoin (250) | 4-Hydroxy-S-Mephenytoin | Positive | m/z 235.2 to 150.0 |
| CYP2D6 | Dextromethorphan (15) | Dextrophan | Positive | m/z 258.1 to 157.1 |
| CYP2E1 | Chlorzoxazone (250) | 6-Hydroxychlorzoxazone | Negative | m/z 183.9 to 119.8 |
| CYP3A4-1 | Midazolam (20) | 1′-Hydroxymidazolam | Positive | m/z 342.1 to 203.1 |
| CYP3A4-2 | Testosterone (200) | 6β-Hydroxytestosterone | Positive | m/z 305.2 to 269.1 |
| CYP2J2 | Astemizole (50) | O-Demethylastemizole | Positive | m/z 445.0 to 204.2 |
| CES2 | Irinotecan (50) | SN38 | Positive | m/z 393.0 to 349.3 |
| UGT | 7-Hydroxycoumarin (100) | 7-Hydroxycoumarin Glucuronide | Negative | m/z 336.9 to 160.9 |
| SULT | 7-Hydroxycoumarin (100) | 7-Hydroxycoumarin Sulfate | Negative | m/z 240.9 to 161.0 |