EXTREMELY THERMOSTABLE GLUTAMATE-DEHYDROGENASE FROM THE HYPERTHERMOPHILIC ARCHAEBACTERIUM PYROCOCCUS-FURIOSUS
EXTREMELY THERMOSTABLE GLUTAMATE-DEHYDROGENASE FROM THE HYPERTHERMOPHILIC ARCHAEBACTERIUM PYROCOCCUS-FURIOSUS
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DOI：
10.1111/j.1432-1033.1991.tb16489.x
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发表时间：
1991-12-18
期刊：
影响因子：
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通讯作者：
SCANDURRA, R
中科院分区：
文献类型：
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作者：
CONSALVI, V;CHIARALUCE, R;SCANDURRA, R
极端嗜热古细菌强烈火球菌含有高水平的NAD（P）依赖性谷氨酸脱氢酶活性。该酶可能参与氮代谢的第一步，催化2-酮戊二酸和氨转化为谷氨酸。纯化至均一的酶是290 kDa的六聚体（亚基质量48 kDa）。纯化的酶的等电聚焦分析显示pI为4.5。该酶对2-酮戊二酸和L-谷氨酸显示出严格的特异性，但利用NADH和NADPH作为辅因子。纯化的酶显示出出色的热稳定性（在100 ℃下热失活的半衰期为12小时），完全不依赖于酶的浓度。P. furiosus谷氨酸脱氢酶占总蛋白的20%;这种升高的浓度引起了关于这种酶在P. furiosus代谢中的作用的问题。
The hyperthermophilic archaebacterium Pyrococcus furiosus contains high levels of NAD(P)-dependent glutamate dehydrogenase activity. The enzyme could be involved in the first step of nitrogen metabolism, catalyzing the conversion of 2-oxoglutarate and ammonia to glutamate. The enzyme, purified to homogeneity, is a hexamer of 290 kDa (subunit mass 48 kDa). Isoelectric-focusing analysis of the purified enzyme showed a pI of 4.5. The enzyme shows strict specificity for 2-oxoglutarate and L-glutamate but utilizes both NADH and NADPH as cofactors. The purified enzyme reveals an outstanding thermal stability (the half-life for thermal inactivation at 100-degrees-C was 12 h), totally independent of enzyme concentration.P. furiosus glutamate dehydrogenase represents 20% of the total protein; this elevated concentration raises questions about the roles of this enzyme in the metabolism of P. furiosus.