caa a22 4500 397494548 CHVBK 20180308164517.0 cr unu---uuuuu 161202e199509 xx s 000 0 eng 10.1093/oxfordjournals.jbchem.a124950 doi (NATIONALLICENCE)oxford-10.1093/oxfordjournals.jbchem.a124950 Properties of Glutamate Dehydrogenase and Its Involvement in Alanine Production in a Hyperthermophilic Archaeon, Thermococcus profundus [Elektronische Daten] [Tetsuo Kobayashi, Sadaharu Higuchi, Kinuko Kimura, Toshiaki Kudo, Koki Horikoshi] Thermococcus profundus, a hyperthermophilic archaeon, did not exhibit detectable glutamine synthetase activity, although the organism possessed an extraordinarily high level of glutamate dehydrogenase (GDH), the content of which reached over 10% of total soluble proteins. This GDH was purified to homogeneity. The enzyme had a molecular weight of 263, 000 and was composed of six homogeneous subunits of molecular weight 43, 000. The enzyme was extremely thermostable with a half life of 1 h at 90°C. Circular dichroism (CD) spectra of the enzyme revealed gradual unfolding of α-helices upon exposure to increasing temperature. The enzyme reaction was strongly biased toward glutamate formation. T.profundus excreted L-alanine into the medium, and the concentration reached 1.5mM. High activity of alanine aminotransferase (AAT) was present in the cells, while no alanine dehydrogenase activity was detected. The alanine formation may be initiated by ammonia uptake by GDH followed by aminotransfer from glutamate to pyruvate by AAT. © by the Journal of Biochemistry Regular Papers nationallicence alanine aminotransferase nationallicence glutamate dehydrogenase nationallicence hyperthermophile nationallicence nitrogen metabolism nationallicence Thermococcus profundus nationallicence Kobayashi Tetsuo Laboratory of Microbiology, The Institute of Physical and Chemical Research (RIKEN), 2-1 Hirosawa, Wako, Saitama 351-01 aut Higuchi Sadaharu Laboratory of Biochemistry, College of Science, Rikkyo (St. Paul's) University Nishi-Ikebukuro, Toshima-ku, Tokyo 171 aut Kimura Kinuko Laboratory of Biochemistry, College of Science, Rikkyo (St. Paul's) University Nishi-Ikebukuro, Toshima-ku, Tokyo 171 aut Kudo Toshiaki Laboratory of Microbiology, The Institute of Physical and Chemical Research (RIKEN), 2-1 Hirosawa, Wako, Saitama 351-01 aut Horikoshi Koki DEEP-STAR Group, Japan Marine Science and Technology Center 2-15 Natsushima-cho, Yokosuka, Kanagawa 237 aut The Journal of Biochemistry Oxford University Press 118/3(1995-09), 587-592 0021-924X 118:3<587 1995 118 jbchem https://doi.org/10.1093/oxfordjournals.jbchem.a124950 text/html Onlinezugriff via DOI 1 other jats NATIONALLICENCE 856 40 https://doi.org/10.1093/oxfordjournals.jbchem.a124950 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Kobayashi Tetsuo Laboratory of Microbiology, The Institute of Physical and Chemical Research (RIKEN), 2-1 Hirosawa, Wako, Saitama 351-01 aut NATIONALLICENCE 700 1- Higuchi Sadaharu Laboratory of Biochemistry, College of Science, Rikkyo (St. Paul's) University Nishi-Ikebukuro, Toshima-ku, Tokyo 171 aut NATIONALLICENCE 700 1- Kimura Kinuko Laboratory of Biochemistry, College of Science, Rikkyo (St. Paul's) University Nishi-Ikebukuro, Toshima-ku, Tokyo 171 aut NATIONALLICENCE 700 1- Kudo Toshiaki Laboratory of Microbiology, The Institute of Physical and Chemical Research (RIKEN), 2-1 Hirosawa, Wako, Saitama 351-01 aut NATIONALLICENCE 700 1- Horikoshi Koki DEEP-STAR Group, Japan Marine Science and Technology Center 2-15 Natsushima-cho, Yokosuka, Kanagawa 237 aut NATIONALLICENCE 773 0- The Journal of Biochemistry Oxford University Press 118/3(1995-09), 587-592 0021-924X 118:3<587 1995 118 jbchem Metadata rights reserved CC BY-NC-4.0 http://creativecommons.org/licenses/by-nc/4.0 nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-oxford