1 Department of Molecular Biology and Genetics - Afgrødegenetik og Bioteknologi, Department of Molecular Biology and Genetics, Science and Technology, Aarhus University2 Cereal Research Centre, Agriculture and Agri-Food Canada3 Department of Plant Physiology, Umeå Plant Science Centre, University of Umeå4 Department of Biology, Memorial University of Newfoundland5 Department of Molecular Biology and Genetics - Afgrødegenetik og Bioteknologi, Department of Molecular Biology and Genetics, Science and Technology, Aarhus University
Oxidation of glycine in photorespiratory pathway is the major flux through mitochondria of C3 plants in the light. It sustains increased intramitochondrial concentrations of NADH and NADPH, which are required to engage the internal rotenone-insensitive NAD(P)H dehydrogenases and the alternative oxidase. We discuss here possible mechanisms of high photorespiratory flux maintenance in mitochondria and suggest that it is fulfilled under conditions where the concentrations of glycine decarboxylase reaction products NADH and CO2 achieve an equilibrium provided by malate dehydrogenase and carbonic anhydrase, respectively. This results in the removal of these products from the glycine decarboxylase multienzyme active sites and in the maintenance of their concentrations at levels sufficiently low to prevent substrate inhibition of the reaction.
Mitochondrion, 2014, Vol 19, Issue B, p. 357-364
Glycine decarboxylase; Non-coupled electron transport; Malate dehydrogenase; Carbonic anhydrase; Photorespiration