Biodegradation pathway of L-glutamatediacetate by Rhizobium radiobacter strain BG-1
Biodegradation pathway of L-glutamatediacetate by Rhizobium radiobacter strain BG-1
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放射根瘤菌菌株BG-1对L-谷氨酸二乙酸的生物降解途径
DOI：
10.1016/j.ibiod.2007.08.003
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发表时间：
2008
影响因子：
4.8
通讯作者：
C. Plugge
中科院分区：
文献类型：
--
作者：
C. G. Ginkel;R. Geerts;P. D. Nguyen;C. Plugge
以L-谷氨酸-N，N-二乙酸酯(L-GLDA)为唯一碳源和能源，从活性污泥中分离到一株好氧细菌。经鉴定，该菌株为放射型根瘤菌。除L-GLDA外，该菌株还利用三乙酸氮酯，并提出了L-GLDA代谢的中间体乙醛和L-谷氨酸。L-GLDA培养的细胞氧化L-GLDA、L-谷氨酸但不氧化亚氨基二乙酸酯和反式-酮基戊二酸酯，这表明作为初始降解反应，羧甲基被去除。L-GLDA的第一个羧甲基的脱除是由依赖NADH的单加氧酶催化的。在放射杆菌无细胞提取液中，还检测到脱氢酶对L-谷氨酸的氧化脱氨作用，导致羟戊二酸的形成。L-格拉达放射杆菌的代谢途径。提出：首先，L-谷氨酸脱氢酶生成L-谷氨酸-N-单乙酸酯(L-谷氨酸-N-单乙酸酯)，而L-谷氨酸-N-单乙酸酯又导致L-谷氨酸。然后，L-谷氨酸导致羟戊二酸，三氯乙酸循环的中间产物。
An aerobic bacterium was isolated from activated sludge in a medium containing l-glutamate-N,N-diacetate (l-GLDA) as sole carbon and energy source. The isolate was identified as a Rhizobium radiobacter species. Besides l-GLDA, the strain utilized nitrilotriacetate (NTA) and proposed intermediates in l-GLDA metabolism such as glyoxylate and l-glutamate. l-GLDA-grown cells oxidized l-GLDA, l-glutamate but not iminodiacetate (IDA), and trans-ketoglutaconate, indicating removal of a carboxymethyl group as an initial degradation reaction. The removal of the first carboxymethyl group of l-GLDA is catalyzed by an NADH-dependent mono-oxygenase. The oxidative deamination of l-glutamate by a dehydrogenase resulting in the formation of oxoglutarate was also detected in cell-free extracts of R. radiobacter sp. A pathway for the metabolism of l-GLDA R. radiobacter sp. is proposed: First, l-GLDA leads to l-glutamate-N-monoacetate (l-GLMA) which in turn leads to l-glutamate. Then, l-glutamate leads to oxoglutarate, an intermediate of the TCA cycle.