Occurrence of two different glutamate dehydrogenase activities in the halophilic bacterium Salinibacter ruber

Maria José Bonete*, Francisco Pérez-Pomares, Susana Díaz, Juan Ferrer, Aharon Oren

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

19 Scopus citations

Abstract

Salinibacter ruber, an extremely halophilic member of the domain Bacteria, has two different cytoplasmic glutamate dehydrogenase activities, marked as GDHI and GDHII. GDHI showed a strong dependence on high salt concentrations for stability, but not for activity, displaying maximal activity in the absence of salts. GDHII depended on high salt concentrations for both activity and stability. It catalyzed amination of 2-oxoglutarate with optimal activity in 3 M KCl at pH 8. No activating effect was found when NaCl was replaced by KCl. Only GDHII displayed activity in the deamination reaction of glutamate with an optimal pH of 9.5. Both enzymes were activated by certain amino acids (L-leucine, L-histidine, L-phenylalanine) and by nucleotides such as ADP or ATP. A low-molecular-mass cytoplasmic fraction was found to be a highly effective activator of GDHII in the presence of high NaCl concentrations.

Original languageAmerican English
Pages (from-to)181-186
Number of pages6
JournalFEMS Microbiology Letters
Volume226
Issue number1
DOIs
StatePublished - 12 Sep 2003

Bibliographical note

Funding Information:
This work was supported by funds from MCYT BIO2002-03197.

Keywords

  • Glutamate dehydrogenase
  • Halophilic enzyme
  • Salinibacter ruber

Fingerprint

Dive into the research topics of 'Occurrence of two different glutamate dehydrogenase activities in the halophilic bacterium Salinibacter ruber'. Together they form a unique fingerprint.

Cite this