title: 5-Dehydro-3-deoxy-D-arabino-heptulosonic acid 7-phosphate. An intermediate in the 3-dehydroquinate synthase reaction.
abstract: 3-Dehydroquinate synthase was purified to homogeneity from Escherichia coli. It was found to be a single polypeptide chain of Mr = approximately 57,000. Reaction mixtures of pure enzyme and the substrate, 3-deoxy-D-arabino-heptulosonic acid 7-phosphate, were incubated for short times and treated with NaB3H4. The resulting 3-deoxyheptonic acid 7-phosphate was degraded with sodium periodate, and formic acid representing C-5 of the substrate was isolated. The presence of 3H in the formate corresponding to 15% of the enzyme was interpreted as indicating a 5-dehydro derivative of the substrate as an intermediate of the reaction. Quinic acid, resulting from reduction of 3-dehydroquinate with NaB3H4, was also isolated and degraded with periodate. The formate from C-4 of the quinate was unlabeled, indicating that 3,4-bisdehydroquinate is not an intermediate.
mesh_terms: D001894:Borohydrides / Q000494:pharmacology; D004926:Escherichia coli / Q000201:enzymology*; D006539:Heptoses; D007700:Kinetics; D008025:Ligases / Q000302:isolation & purification / Q000378:metabolism*; D008970:Molecular Weight; D019761:Phosphorus-Oxygen Lyases; D011801:Quinic Acid / Q000031:analogs & derivatives; D013400:Sugar Acids
chemical_list: D001894:Borohydrides; D006539:Heptoses; D013400:Sugar Acids; D011801:Quinic Acid; C020001:3-dehydroquinate synthetase; D019761:Phosphorus-Oxygen Lyases; D008025:Ligases