1.1.1.44 | 6-phospho-D-gluconate + NADP+ = D-ribulose 5-phosphate + CO2 + NADPH + H+ |
reductive carboxylation of ribulose-5-phosphate by 6PGDH is investigated using kinetic isotope effects. In the absence of 6-phosphogluconate, a slow step, which precedes the chemical process, is rate-limiting for the reaction, whereas in the presence of 6-phosphogluconate, the rate-limiting step follows the isotope-sensitive step. Full activity of 6PGDH is achieved when one subunit carries out the catalysis and the other subunit carries an unreacted 6-phosphogluconate (allosteric activator) |
712444 |