Table 4.
Kinetic resolution of rac-ibuprofen ethyl ester using the free and corresponding CLEA-LC counterpart with the same enzyme content from each preparation.
| Enzyme | Free Form | CLEA-LC Form | ||||
|---|---|---|---|---|---|---|
| C (%) | eep (%), SP. | E | C (%) | eep (%), sp. | E | |
| CRL | 49 | 97, (S) | >200 | 40 | 99, (S) | >200 |
| CAL-B | 76 | 27, (R) | ---- | 64 | 30, (R) | ---- |
| CAL-B* | 25 | 15, (R) | ---- | 45 | 48, (R) | 8.47 |
| CAL-A | 23 | 22, (S) | 3 | 46 | 66, (R) | 14.30 |
| RML | 81 | 22, (S) | ---- | 47 | 44, (S) | 9.24 |
| LU | 8 | 06, (R) | 2 | 33 | 47, (R) | 5.56 |
| TLL | 74 | 75, (S) | ---- | 3.4 | >99 | 2.24 |
Conditions: CRL (0.115 mg), CAL-B (0.115 mg), CAL-B* (0.045 mg), CAL-A (2.4 mg), TLL (5.14 mg), LU (1.26 mg), RML (2.5 mg), 30 mg of substrate (rac-ibuprofen ethyl ester), 10 mL of 10 mM Tris-HCl 7.0, 250 rpm, 37 °C, 24 h. C (%): overall conversion, eep: enantiomeric excess of the product (R or S ibuprofen), SP.: stereopreference of the catalyst; E: enantioselectivity (enantiomeric ratio, ratio between the specificity constants (kcat/KM) for both enantiomers), calculated as E = ln[(1 − C) × (1 + eep)]/ln[(1 − C × (1 − eep)], eep and C as decimals (≤1) [65,66]).