Table II.
The substrate specificity of UGT74M1
UGT74M1 assays were performed as described in “Materials and Methods” using the radiochemical assay. The substrates for which no activity was detected are α-amyrin, β-amyrin, asiatic acid, benzoic acid, caffeic acid, cholesterol, cyanidin, diosgenin, erythrodiol, lupeol, oleanolic acid, quercetin, salicylic acid, and spinasterol.
| Substrate | Relative Activity | C-23 | C-16 |
|---|---|---|---|
| % | |||
| 16α-Hydroxygypsogenic acid | 177 | COOH | OH |
| Gypsogenic acid | 100 | COOH | H |
| Gypsogenin | 22 | CHO | H |
| Quillaic acid | 19 | CHO | OH |
| Echinocystic acid | 9 | CH3 | OH |
| Hederagenin | 4.5 | CH2OH | H |
| Betulinic acid | 2.5 | CH3 | H |