Table 2.
Enzyme | Vc*, µmol⋅mg−1⋅h−1 | Kc*, µM CO2 | Ko*†, µM O2 | Vc/Kc‡ | Ko/Kc‡ | Vc/Vo‡ | Ω (VcKo/VoKc)‡ |
Wild type | 110 ± 9 | 30 ± 2 | 523 ± 18 | 3.7 | 17 | 3.5 | 61 ± 2 |
Helix AB | 13 ± 3 | 35 ± 3 | 299 ± 59 | 0.4 | 7 | 7.7 | 54 ± 2 |
Carboxylation (c) and oxygenation (o) kinetic properties of Rubisco purified from spinach hybrid have been determined by the authors before (mutant SSSO in ref. 21): Vc = 97, Kc = 34, Ko = 539, Vc/Kc = 2.9; Ko/Kc = 16; Vc/Vo = 4.1; Ω = 65. K (in micromolar concentration) is the Km and V (in micromolar hour−1 milligram−1) is the Vmax of purified and activated Rubisco.
*Values are the means ± 1 SD of three biological replicates.
†The Michaelis–Menten constant is measured as the O2 inhibition constant for the carboxylation reaction (Kio) and is assumed to equal Ko (also noted KmO2).
‡Calculated values.