Derived kinetic parameters for lidocaine N-deethylation by HLM and rCYP1A2, in the absence and presence of BSA
| Liver | Without BSA | With 2% BSA | ||||||
|---|---|---|---|---|---|---|---|---|
| Km1 | Vmax1 | Km2 | Vmax2 | Km1 | Vmax1 | Km2 | Vmax2 | |
| μM | pmol/min · min | μM | pmol/min · min | μM | pmol/min · min | μM | pmol/min · min | |
| HL7 | 215 | 829 | 2088 | 4450 | 34.1 | 479 | 1462 | 5130 |
| HL10 | 135 | 650 | 1762 | 3939 | 51.1 | 643 | 1303 | 4005 |
| HL12 | 246 | 1745 | 1729 | 7067 | 119 | 2407 | 2040 | 7524 |
| HL40 | 149 | 688 | 1313 | 4088 | 49.5 | 1130 | 1209 | 3850 |
| Mean ± S.D. | 186 ± 53 | 978 ± 517 | 1723 ± 318 | 4886 ± 1470 | 63.4 ± 37.8* | 1165 ± 873 | 1504 ± 373 | 5127 ± 1697 |
| HL29 | 1500 | 3441 | 76 | 1030 | 2865 | 3988 | ||
| rCYP1A2a | 4940 ± 204b | 274 ± 6 | 822 ± 46*,b | 189 ± 14* | ||||
↵* Significantly different (P < 0.05) from corresponding parameter derived from incubations without BSA.
↵a Data are means ± S.D. from four experiments. For Vmax1 and Vmax2, picomoles per minute per picomoles of P450 with rCYP1A2 as the enzyme source.
↵b S50 (negative cooperative kinetics). Values of n were 0.73 ± 0.01 and 0.69 ± 0.04 in the absence and presence of BSA, respectively.