Schinkinger M F, Redl B, Stöffler G
Institut für Mikrobiologie, Medizinische Fakultät der Universität Innsbruck, Austria.
Biochim Biophys Acta. 1991 Jan 23;1073(1):142-8. doi: 10.1016/0304-4165(91)90194-l.
Glutamate dehydrogenase (L-glutamate:NAD(P)+ oxidoreductase, deaminating, EC 1.4.1.3.) of the extreme thermophilic archaebacterium Sulfolobus solfataricus was purified to homogeneity by (NH4)2SO4 fractionation, anion-exchange chromatography and affinity chromatography on 5'-AMP-Sepharose. The purified native enzyme had a Mr of about 270,000 and was shown to be a hexamer of subunit Mr of 44,000. It was active from 30 to 95 degrees C, with a maximum activity at 85 degrees C. No significant loss of enzyme activity could be detected, either after incubation of the purified enzyme at 90 degrees C for 60 min, or in the presence of 4 M urea or 0.1% SDS. The enzyme was catalytically active with both NADH and NADPH as coenzyme and was specific for 2-oxoglutarate and L-glutamate as substrates. With respect to coenzyme utilization the Sulfolobus solfataricus glutamate dehydrogenase resembled more closely the equivalent enzymes from eukaryotic organisms than those from eubacteria.
通过硫酸铵分级沉淀、阴离子交换色谱和5'-AMP-琼脂糖亲和色谱，将嗜热古细菌嗜热栖热菌的谷氨酸脱氢酶（L-谷氨酸：NAD(P)+氧化还原酶，脱氨基，EC 1.4.1.3.）纯化至同质。纯化后的天然酶的相对分子质量约为270,000，显示为亚基相对分子质量为44,000的六聚体。其活性温度范围为30至95摄氏度，在85摄氏度时活性最高。无论是将纯化后的酶在90摄氏度下孵育60分钟，还是在4 M尿素或0.1% SDS存在的情况下，均未检测到酶活性的显著损失。该酶以NADH和NADPH作为辅酶均具有催化活性，并且对底物2-氧代戊二酸和L-谷氨酸具有特异性。就辅酶利用而言，嗜热栖热菌谷氨酸脱氢酶与真核生物中的等效酶比与真细菌中的等效酶更为相似。
