Table 2.
Oxidation of fenoterol and salbutamol by LPO/H2O2 - Effect of inhibitors. H2O2 was generated by glucose (1 mM) glucose oxidase (0.2 μg/mL). Oxidation of fenoterol (50 μM) and salbutamol (100 μM) was carried out in 0.1 M potassium phosphate buffer (pH 7.0) containing 0.1 mM DTPA in the presence of LPO (158 nM LPO for fenoterol and 216 nM for salbutamol). The extent of inhibition was determined by measuring ΔA315 during 30 min reaction and is expressed as % of control (mean ± SE from at least two determinations).
| Amount of metabolite formed ΔA315(%) | ||
|---|---|---|
| Fenoterol |
Salbutamol |
|
| Control | 100 | 100 |
| NaN3 (1 mM) | 45.5 ± 3.9 | 17.4 ± 7.1 |
| NaCN (1 mM) | 95.2 ± 5.3 | 80.0 ± 3.2 |
| NaSCN (0.1 mM) | 22.8 ± 3.8 | 5.5 ± 7.3 |
| GSH (0.1 mM) | 38.1 ± 3.2 | 42.7 ± 3.4 |
| Methionine (0.1 mM) | 103.7 ± 2.0 | 105.5 ± 16.2 |
| Methionine (2 mM) | 95.0 ± 3.5 | ----------- |
| Methimazole (20 μM) | 30.0 ± 2.9 | 16.7 ± 4.6 |