Table 1.
Specific activities (nmol/min/mg of protein) and mRNA expression (normalized to GAPDH) of conjugation enzymes in proliferating (P) and differentiated (D) Caco-2 cells.
| Enzyme | P | D |
|---|---|---|
| GST | ||
| Activity | 249 ± 13 | 268 ± 20 |
| mRNA GSTA1/2 | 1.00 ± 0.04 | *** 9.15 ± 0.45 |
| mRNA GSTP1 | 1.00 ± 0.19 | *** 2.60 ± 0.14 |
| SULT | ||
| Activity | 20.7 ± 1.3 | ** 14.1 ± 1.6 |
| mRNA SULT1A1/3 | 1.00 ± 0.03 | *** 7.65 ± 0.33 |
| COMT | ||
| Activity | 10.5 ± 0.9 | 12.9 ± 0.3 |
| mRNA COMT | 1.00 ± 0.09 | *** 3.17 ± 0.14 |
| UGT | ||
| Activity | n.d. | n.d. |
| mRNA UGT1A | 1.00 ± 0.09 | *** 2.17 ± 0.08 |
Values represent means ± SD of three samples. Significance of differences of D cells from P cells was determined by a Students t-test (** p < 0.01, *** p < 0.001); n.d. = not detected. GAPDH: glyceraldehyde-3-phosphate dehydrogenase; GST: Glutathione S-transferases; SULT: Sulfotransferases; COMT: Catechol-O-methyltransferases; UGT: UDP-glucuronosyltransferases.