Table II.
Catalase activity (U mg−1 protein) in cell extracts of yeast treated with different menadione concentrations (5–100 mM) in phosphate or bicarbonate buffers. Data shown are the mean ± SEM (n = 4).
| Buffer | Menadione (mM)
|
|||||
|---|---|---|---|---|---|---|
| 0 | 5 | 10 | 25 | 50 | 100 | |
| 25 mM | ||||||
| Phosphate | 223 ± 33 | 208 ± 28 | 203 ± 27 | 217 ± 25 | 177 ± 20 | 190 ± 17 |
| Bicarbonate | 193 ± 26 | 208 ± 26 | 174 ± 22 | 196 ± 18 | 181 ± 22 | 194 ± 34 |
|
| ||||||
| 50 mM | ||||||
| Phosphate | 209 ± 9 | 177 ± 14 | 180 ± 14 | 174 ± 13 | 176 ± 17 | 151 ± 24* |
| Bicarbonate | 175 ± 7 | 174 ± 5 | 168 ± 7 | 168 ± 6 | 162 ± 6 | 151 ± 5 |
*
Significantly different from respective controls (untreated cells), P<0.05.