Affinity of RuBisCO to CO2

Range at 20˚C ~50µM: at 0˚C ~15 µM
Organism Diatoms
Reference Kranz SA, Young JN, Hopkinson BM, Goldman JA, Tortell PD, Morel FM. Low temperature reduces the energetic requirement for the CO2 concentrating mechanism in diatoms. New Phytol. 2015 Jan205(1):192-201. doi: 10.1111/nph.12976 p.198 left column 3rd paragraphPubMed ID25308897
Primary Source Young JN, Goldman JA, Kranz SA, Tortell PD, Morel FM. Slow carboxylation of Rubisco constrains the rate of carbon fixation during Antarctic phytoplankton blooms. New Phytol. 2015 Jan205(1):172-81. doi: 10.1111/nph.13021PubMed ID25283055
Comments P.198 left column 3rd paragraph: "Low temperatures affect several physical, chemical and biochemical processes that are important to the functioning of a CCM [carbon concentrating mechanism] in psychrophilic phytoplankton: the CO2 solubility in seawater increases from c. 13 μM at 20°C to c. 25 μM at 0°C at equilibrium with the atmosphere, the diffusion coefficient of dissolved CO2 decreases (by a factor of 2 between 20 and 0°C (Boudreau, 1997)), the affinity of enzymes for their substrate changes (e.g. the KC of diatom Rubisco decreases from c. 50 μM at 20°C to c. 15 μM at 0°C (primary source)), and the turnover rate of most enzymes decrease (e.g. by a factor of 10 for Rubisco between 20 and 0°C (primary source)), although some cold‐adapted enzymes maintain relatively high kinetics (as is apparently the case for carbonic anhydrase in the diatoms in the WAP [Western Antarctic Peninsula])."
Entered by Uri M
ID 116832