On the regulatory significance of inhibitors acting on non‐equilibrium enzymes in the Calvin photosynthesis cycle

Control analyses and kinetic model studies have been performed in order to obtain quantitative information on the regulatory significance of 12 experimentally well‐documented inhibitory interactions of Calvin cycle intermediates with the four non‐equilibrium cycle enzymes. Evidence is presented to show that none of these interactions contributes significantly to the cycle flux control over the range of external orthophosphate concentrations where the reaction cycle shows close to optimal activity. Contrary to what has been generally supposed, the examined inhibitions appear to be of little interest for our understanding of the biological regulation of the Calvin photosynthesis cycle under conditions of light and carbon dioxide saturation.