Table II.
Summary of kinetic parameters of HCO3− and CO2 transport in fast-induced and noninduced cyanobacterial cells
| Kinetic Parameters | High-Ci Cells | Low-Ci Cells | Fast-Induced Cells
|
|
|---|---|---|---|---|
| +CA | −CA | |||
| PCC7002 | ||||
| HCO3− transport | ||||
| Vmax (μmol mg−1 Chl h−1) | 461 ± 35 | 521 ± 49 | 495 ± 45 | 479 ± 48 |
| K1/2(HCO3−) (μm) | 167 ± 22 | 9.0 ± 3.2 | 23.5 ± 3.0 | 153 ± 14 |
| CO2 transport | ||||
| Vmax (μmol mg−1 Chl h−1) | 167 ± 11 | 176 ± 14 | 161 ± 10 | 165 ± 14 |
| K1/2(CO2) (μm) | 2.8 ± 0.3 | 0.5 ± 0.1 | 3.8 ± 0.4 | 3.5 ± 0.5 |
| PCC7942 | ||||
| HCO3−-transport | ||||
| Vmax (μmol mg−1 Chl h−1) | 206 ± 25 | 230 ± 19 | 248 ± 10 | n.d.a |
| K1/2(HCO3−) (μm) | 248 ± 21 | 9.0 ± 0.7 | 15.5 ± 3.8 | n.d. |
| CO2 transport | ||||
| Vmax (μmol mg−1 Chl h−1) | 116 ± 11 | 103 ± 14 | 133 ± 14 | n.d. |
| K1/2(CO2) (μm) | 3.6 ± 0.9 | 0.5 ± 0.1 | 3.4 ± 0.4 | n.d. |
High- and low-Ci cells of Synechococcus sp. strain PCC7002 and Synechococcus sp. strain PCC7942 were grown continuously on 2% CO2 and 20 μL of CO2 L−1. Fast-induced cells were obtained from high-Ci cells, which were allowed to run out of Ci for 4 min (strain PCC7002) and 10 min (strain PCC7942). When indicated, CA (100 Wilbur-Anderson units mL−1) was included during the Ci-depletion period. The data were obtained from experiments similar to those shown in Figure 3 and represent the mean ± sd from three to four independent experiments.
a
n.d, Not determined.