Varying substrate | Product |
K
0.5
(μM) |
K
i
(μM) |
V
max
(nmol min−1 mg−1) |
k
cat
(s−1) |
k
cat
/K
0.5
(s−1 M−1) |
---|
Cyanidin | Epicatechina
| 114.2 ± 19.0 | 631.5 ± 119.9 | 11.57 ± 1.13 | 0.0072 ± 0.0007 | 65.4 ± 13.8 |
Cyanidin | Catechina
| 116.5 ± 10.7 | 583.8 ± 116.1 | 8.32 ± 0.73 | 0.0052 ± 0.0004 | 45.4 ± 6.42 |
NADPH | Epicatechinb
| 103.5 ± 7.4 | - | 3.34 ± 0.21 | 0.0021 ± 0.0001 | 20.1 ± 0.49 |
NADPH | Catechinb
| 102.3 ± 7.8 | - | 2.44 ± 0.18 | 0.0015 ± 0.0001 | 14.9 ± 1.03 |
- The K
cat
(also referred to as turnover rate) was calculated using a molecular mass of 37.4Â kDa for the final recombinant PvANR1 preparation, following removal of the His6 tag
-
aA non-linear regression model for substrate inhibition (as described under Methods) was used to determine apparent kinetic parameters for cyanidin. These assays were performed at a fixed NADPH concentration of 800 μM
-
bThe Hill equation was utilized to determine kinetic parameters for NADPH. These assays were performed at a fixed cyanidin concentration of 100 μM; the Hill coefficient for epicatechin and catechin formation was 2.5 ± 0.19 and 2.5 ± 0.15, respectively