Table I.
Catalytic activities of C4H and CPR in microsomal fractions prepared from C4H- or C4H/CPR-expressing yeast strains
| CPR Acta
|
||||
|---|---|---|---|---|
| Construct | C4H Acta | (Relative Act)b | NADH | NADPH |
| C4H/− | 0.9 ± 0.1 | (1.0 ± 0.1) | 528 ± 28 | 344 ± 25 |
| C4H/CPR1 | 2.8 ± 0.2 | (9.7 ± 1.3) | 504 ± 39 | 1,848 ± 95 |
| C4H/CPR2 | 7.4 ± 0.3 | (14.3 ± 1.3) | 437 ± 30 | 1,096 ± 60 |
a
Specific activities are given as nmol p-coumarate min−1 microsomal protein mg−1 for the C4H assay and nmol cyt c reduction min−1 microsomal protein mg−1 for the CPR assay. Each value is a mean ± se from four independent microsomal preparations.
b
For relative activities, the C4H-specific activities were normalized as arbitrary units derived from the densitometric quantification of the C4H signals detected by enhanced chemiluminescence (ECL) immunoblot analysis. The C4H activity from the C4H-only-expressing yeast was used as a reference to calculate relative activities in the other strains.