title: The chemical mechanism of sheep liver 6-phosphogluconate dehydrogenase. A Schiff-base intermediate is not involved.
abstract: [2-18O]Ribulose 5-phosphate was prepared and shown to be converted enzymically by 6-phosphogluconate dehydrogenase from sheep liver into 6-phosphogluconate with complete retention of the heavy isotope. This finding unequivocally excludes the possibility of a Schiff-base mechanism for the enzyme. The involvement of metal ions has already been excluded, and other possible mechanisms are discussed. The enzyme was purified by an improved large-scale procedure, which is briefly described.
mesh_terms: D000818:Animals; D003653:Decarboxylation; D005942:Gluconates / Q000378:metabolism; D008099:Liver / Q000201:enzymology*; D013058:Mass Spectrometry; D008956:Models, Chemical; D010084:Oxidation-Reduction; D010734:Phosphogluconate Dehydrogenase / Q000302:isolation & purification / Q000378:metabolism*; D012274:Ribulosephosphates / Q000378:metabolism; D012756:Sheep
chemical_list: D005942:Gluconates; D012274:Ribulosephosphates; C031524:ribulose 5-phosphate; D010734:Phosphogluconate Dehydrogenase; C008884:6-phosphogluconic acid