Table I.
Kinetic parameters of various enzymes for Arabidopsis Fds
| Fd Species
|
Photosystem I
|
Leaf FNR
|
Root FNR
|
Sulfite Reductase
|
||||
|---|---|---|---|---|---|---|---|---|
| Km | Vmax | Km | Vmax | Km | Vmax | Km | Vmax | |
| μm Fd ± sd | μmol NADPH μg-1 chlorophyll s-1 ± sd | μm Fd ± sd | μmol μmol-1 enzyme s-1 ± sd | μm Fd ± sd | μmol μmol-1 enzyme s-1 ± sd | μm Fd ± sd | μmol μmol-1 enzyme s-1 ± sd | |
| AtFd1 | 0.16 ± 0.07 | 0.020 ± 0.004 | 4.0 ± 0.5 | 61.6 ± 9. | 18.0 ± 5.6 | 197 ± 21 | 6.2 ± 0.97 | 7.5 ± 1.9 |
| AtFd2 | 0.18 ± 0.09 | 0.023 ± 0.007 | 2.8 ± 0.3 | 61.2 ± 16 | 19.0 ± 5.7 | 209 ± 39 | 5.2 ± 1.3 | 7.2 ± 0.8 |
| AtFd3 | 3.6 ± 0.8 | 0.025 ± 0.006 | 4.9 ± 1.4 | 79.4 ± 17 | 4.7 ± 0.5 | 231 ± 69 | 2.1 ± 0.33 | 13.7 ± 2.6 |
| AtFd4 | — | — | 27.4 ± 8.1 | 90.6 ± 14 | 14.7 ± 1.6 | 334 ± 78 | — | — |