Table 2.
Rubisco carboxylation kinetics of the analyzed polar populations measured at 25 °C and 4 °C, the ratio between 25 °C and 4 °C measurements for each kinetic parameter, and Rubisco content at the growth conditions
| Species | K c (µM) | k cat c (s −1) | k cat c /K c (s −1 mM −1) | [Rubisco]/ [TSP] (%) | ||||||
| 25 °C | 4 °C | 25 °C/4 °C | 25 °C | 4 °C | 25 °C/4 °C | 25 °C | 4 °C | 25 °C/4 °C | ||
| Rhodophyta | ||||||||||
| Phycodrys rubens | 18.9±0.8 | 4.8±0.7 | 3.94±0.40 | 1.76±0.03 | 0.14±0.01 | 12.2±0.9 | 93.5±3.8 | 30.1±2.0 | 3.11±0.10 | 8.0±0.7 |
| Ptilota gunneri | 14.4±1.1 | 5.1±0.6 | 2.83±0.12 | 1.60±0.23 | 0.17±0.03 | 9.3±0.5 | 110.7±7.2 | 33.8±2.4 | 3.27±0.05 | 6.6±0.9 |
| Devaleraea ramentacea | 17.5±1.0 | 5.6±0.8 | 3.13±0.26 | 2.59±0.16 | 0.34±0.04 | 7.6±0.6 | 148.1±8.3 | 60.9±0.9 | 2.43±0.14 | 7.4±1.7 |
| Palmaria palmata | 15.9±0.6 | 4.9±0.2 | 3.24±0.01 | 2.08±0.05 | 0.27±0.01 | 7.8±0.2 | 131.3±8.1 | 54.6±2.1 | 2.40±0.07 | 9.9±0.6 |
| Palmaria decipiens | 17.4±1.2 | 5.0±0.2 | 3.50±0.12 | 2.43±0.16 | 0.31±0.01 | 7.8±0.2 | 139.7±3.3 | 62.9±0.3 | 2.22±0.05 | 7.8±0.1 |
| Ochrophyta (Phaeophyceae) | ||||||||||
| Alaria esculenta | 23.6±1.0 | 4.1±0.5 | 5.85±1.01 | 2.13±0.14 | 0.23±0.02 | 9.5±1.3 | 90.3±4.3 | 55.5±1.9 | 1.63±0.06 | 17.4±1.8 |
| Desmarestia aculeata | 13.3±0.6 | 2.1±0.3 | 6.44±0.89 | 1.37±0.12 | 0.12±0.02 | 11.3 ±1.3 | 103.3±12 | 61.0±22 | 1.79±0.41 | 17.7±4.7 |
| Laminaria solidungula | 18.5±1.3 | 3.9±0.8 | 4.96±1.23 | 1.60±0.12 | 0.17±0.02 | 9.2±0.7 | 86.6±6.2 | 47.1±14 | 1.92±0.41 | 30.1±1.4 |
| Laminaria digitata | 17.0±1.0 | 4.0±0.3 | 4.25±0.40 | 1.42±0.28 | 0.10±0.02 | 16.4±2.9 | 84.3±20 | 26.1±2.8 | 3.84±0.36 | 24.7±7.5 |
| Saccharina latissima | 19.4±1.2 | 3.8±0.4 | 4.99±0.29 | 1.79±0.18 | 0.16±0.03 | 10.8±0.6 | 92.5±7.5 | 43.3±8.4 | 2.17±0.23 | 37.3±6.1 |
| Himantothallus grandifolius | 18.1±1.1 | 4.4±0.8 | 4.14±0.49 | 2.08±0.02 | 0.23±0.01 | 9.2±0.6 | 115±7.4 | 51.7±6.5 | 2.23±0.16 | n.d. |
| Chlorophyta | ||||||||||
| Acrosiphonia arcta (Arctic) | 52.8±1.6 | 17.7±2.6 | 3.01±0.33 | 5.08±0.15 | 0.82±0.03 | 6.2±0.1 | 96.2±2.7 | 46.7±5.7 | 2.07±0.22 | 7.6±0.1 |
| Control | ||||||||||
| Triticum aestivum | 9.6±0.4 | 3.1±0.1 | 3.06±0.14 | 2.20±0.23 | 0.20±0.01 | 11.2±0.6 | 230.1±28 | 62.8±4.1 | 3.66±0.28 | 42.3±2.5 |
k cat c, Rubisco carboxylase turnover rate; Kc, Michaelis–Menten affinity constant for CO2; kcatc/Kc, carboxylation efficiency; [Rubisco]/[TSP], percentage of Rubisco in the total soluble protein. Data are means ±SD (n=3–5 independent thalli). n.d., Not determined.