An NAD(P)-dependent glutamate dehydrogenase was purified to homogeneity from the thermoacidophilic archaebacterium Sulfolobus solfataricus. The enzyme is a hexamer (subunit mass 45 kDa) which dissociates into lower state of association when submitted to gel filtration. Isoelectric focusing analysis of the purified enzyme showed a pI of 5.7 and occasionally revealed microheterogeneity. The enzyme is strictly specific for the natural substrates 2-oxoglutarate and L-glutamate, but is active with both NADH and NADPH. S. solfataricus glutamate dehydrogenase revealed a high degree of thermal stability (at 80-degrees-C the half-life was 15 h) which was strictly dependent on the protein concentration. Very high levels of glutamate dehydrogenase were found in this archaebacterium which suggests that the conversion of 2-oxoglutarate and ammonia to glutamate is of central importance to the nitrogen metabolism in this bacterium.
GLUTAMATE DEHYDROGENASE FROM THERMOACIDOPHILIC ARCHAEBACTERIUM Sulfolobus solfataricus / Consalvi, Valerio; Chiaraluce, Roberta; Politi, Laura; A., Gambacorta; M., DE ROSA; Scandurra, Roberto. - In: EUROPEAN JOURNAL OF BIOCHEMISTRY. - ISSN 0014-2956. - 196:(1991), pp. 459-467. [10.1111/j.1432-1033.1991.tb15837.x]
GLUTAMATE DEHYDROGENASE FROM THERMOACIDOPHILIC ARCHAEBACTERIUM Sulfolobus solfataricus.
CONSALVI, Valerio;CHIARALUCE, Roberta;POLITI, Laura;SCANDURRA, Roberto
1991
Abstract
An NAD(P)-dependent glutamate dehydrogenase was purified to homogeneity from the thermoacidophilic archaebacterium Sulfolobus solfataricus. The enzyme is a hexamer (subunit mass 45 kDa) which dissociates into lower state of association when submitted to gel filtration. Isoelectric focusing analysis of the purified enzyme showed a pI of 5.7 and occasionally revealed microheterogeneity. The enzyme is strictly specific for the natural substrates 2-oxoglutarate and L-glutamate, but is active with both NADH and NADPH. S. solfataricus glutamate dehydrogenase revealed a high degree of thermal stability (at 80-degrees-C the half-life was 15 h) which was strictly dependent on the protein concentration. Very high levels of glutamate dehydrogenase were found in this archaebacterium which suggests that the conversion of 2-oxoglutarate and ammonia to glutamate is of central importance to the nitrogen metabolism in this bacterium.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
