Table 2.
Kinetic Parameters and Inhibitory Properties of Acetazolamide for Different CA Isozymes, Including the Mutant CA XII15
| Isoenzyme | kcat (s−1) | KM (mM) | kcat/KM (M−1s−1) | KI (Acetazolamidea) (nM) | Subcellular Localization |
|---|---|---|---|---|---|
| hCA I | 2.0 × 105 | 4.0 | 5.0 × 107 | 250 | cytosol |
| hCA II | 1.4 × 106 | 9.3 | 1.5 × 108 | 12 | cytosol |
| hCA IV | 1.1 × 106 | 21.5 | 5.1 × 107 | 74 | GPI-anchored |
| hCA VI | 3.4 × 105 | 6.9 | 4.9 × 107 | 11 | secreted |
| hCA IX (catalytic domain) | 3.8 × 105 | 6.9 | 5.5 × 107 | 25 | transmembrane |
| hCA IX (full length) | 1.1 × 106 | 7.5 | 1.5 × 108 | 16 | transmembrane |
| hCA XII | 4.2 × 105 | 12.0 | 3.5 × 107 | 5.7 | transmembrane |
| hCA XII mutant | 3.0 × 105 | 11.9 | 2.5 × 107 | 9.9 | transmembrane |
a
5-acetamido-1,3,4-thiadiazole-2-sulfonamide.