Comparison of Km,kcat/Km, andKi of hCE-1 and hCE-2 for drug esters
| hCE-1 | hCE-2 | |||||
|---|---|---|---|---|---|---|
| Km | kcat/Km | Ki | Km | kcat/Km | Ki | |
| mM | mM−1 · min−1 | mM | mM | mM−1 · min−1 | mM | |
| Substrate | ||||||
| Meperidine | 1.9 ± 0.3 | 0.35 ± 0.02 | 0 | |||
| Cocaine | 0.12 | 0.5 | 0.39 | 18.4 | ||
| Heroin | 6.3 | 69.0 | 6.8 | 314.0 | ||
| 6-Acetylmorphine | 8.3 | 0.024 | 0.13 | 22.0 | ||
| 4-Methylumbelliferyl acetate | 0.8 | 2,000 | 0.15 | 60,000 | ||
| Inhibitor | ||||||
| Meperidine | 1.30 ± 0.12 | 0.63 ± 0.06 | ||||
| Propoxyphene | 0.44 ± 0.03 | 0.44 ± 0.07 | ||||
Km and kcat/Kmdata for cocaine and 4-methylumbelliferyl acetate were obtained fromPindel et al. (1997) and heroin and 6-acetylmorphine from Kamendulis et al. (1996). The Ki data were obtained from the competitive inhibition of 4-methylumbelliferyl acetate hydrolysis.