[9] Preparation of optically pure isotopically labeled l-glutamate

摘要: Publisher Summary Commercially available preparations of radioactively labeled L-glutamate commonly contain small amounts D-glutamate. The presence as little a 0.1% impurity D-glutamate in an preparation may lead to unreliable results, especially studies on the metabolism 5-oxo-L-proline. A highly active enzyme (D-glutamate cyclase) is present certain mammalian tissues (notably kidney and liver) that catalyzes rapid conversion 5-oxo-D-proline. Significant concentrations 5-oxo-D-proline are found human blood plasma excreted urine normal humans substantial amounts. Several procedures useful dealing with this problem. In one approach, commercially radiolabeled treated partially purified cyclase convert Another approach involves synthesis by action glutamate dehydrogenase α-ketoglutarate.