PMID- 17932305
OWN - NLM
STAT- MEDLINE
DCOM- 20080331
LR  - 20231213
IS  - 0032-0889 (Print)
IS  - 1532-2548 (Electronic)
IS  - 0032-0889 (Linking)
VI  - 145
IP  - 4
DP  - 2007 Dec
TI  - The isoenzyme 7 of tobacco NAD(H)-dependent glutamate dehydrogenase exhibits high 
      deaminating and low aminating activities in vivo.
PG  - 1726-34
AB  - Following the discovery of glutamine synthetase/glutamate (Glu) synthase, the 
      physiological roles of Glu dehydrogenase (GDH) in nitrogen metabolism in plants 
      remain obscure and is the subject of considerable controversy. Recently, 
      transgenics were used to overexpress the gene encoding for the beta-subunit 
      polypeptide of GDH, resulting in the GDH-isoenzyme 1 deaminating in vivo Glu. In 
      this work, we present transgenic tobacco (Nicotiana tabacum) plants 
      overexpressing the plant gdh gene encoding for the alpha-subunit polypeptide of 
      GDH. The levels of transcript correlated well with the levels of total GDH 
      protein, the alpha-subunit polypeptide, and the abundance of GDH-anionic 
      isoenzymes. Assays of transgenic plant extracts revealed high in vitro aminating 
      and low deaminating activities. However, gas chromatography/mass spectrometry 
      analysis of the metabolic fate of (15)NH(4) or [(15)N]Glu revealed that 
      GDH-isoenzyme 7 mostly deaminates Glu and also exhibits low ammonium assimilating 
      activity. These and previous results firmly establish the direction of the 
      reactions catalyzed by the anionic and cationic isoenzymes of GDH in vivo under 
      normal growth conditions and reveal a paradox between the in vitro and in vivo 
      enzyme activities.
FAU - Skopelitis, Damianos S
AU  - Skopelitis DS
AD  - Department of Biology, University of Crete, 71409 Heraklion, Greece.
FAU - Paranychianakis, Nikolaos V
AU  - Paranychianakis NV
FAU - Kouvarakis, Antonios
AU  - Kouvarakis A
FAU - Spyros, Apostolis
AU  - Spyros A
FAU - Stephanou, Euripides G
AU  - Stephanou EG
FAU - Roubelakis-Angelakis, Kalliopi A
AU  - Roubelakis-Angelakis KA
LA  - eng
SI  - GENBANK/X86924
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
DEP - 20071011
PL  - United States
TA  - Plant Physiol
JT  - Plant physiology
JID - 0401224
RN  - 0 (Anions)
RN  - 0 (Isoenzymes)
RN  - 0 (Protein Subunits)
RN  - 3KX376GY7L (Glutamic Acid)
RN  - EC 1.4.1.2 (Glutamate Dehydrogenase)
SB  - IM
MH  - Anions/metabolism
MH  - Gas Chromatography-Mass Spectrometry
MH  - Glutamate Dehydrogenase/genetics/*metabolism
MH  - Glutamic Acid/*metabolism
MH  - Isoenzymes/metabolism
MH  - Magnetic Resonance Spectroscopy
MH  - Molecular Sequence Data
MH  - Plants, Genetically Modified/metabolism
MH  - Protein Subunits/metabolism
MH  - Nicotiana/*enzymology/genetics/metabolism
MH  - Transcription, Genetic
MH  - Vitis/*genetics
PMC - PMC2151676
EDAT- 2007/10/13 09:00
MHDA- 2008/04/01 09:00
PMCR- 2007/12/01
CRDT- 2007/10/13 09:00
PHST- 2007/10/13 09:00 [pubmed]
PHST- 2008/04/01 09:00 [medline]
PHST- 2007/10/13 09:00 [entrez]
PHST- 2007/12/01 00:00 [pmc-release]
AID - pp.107.107813 [pii]
AID - 107813 [pii]
AID - 10.1104/pp.107.107813 [doi]
PST - ppublish
SO  - Plant Physiol. 2007 Dec;145(4):1726-34. doi: 10.1104/pp.107.107813. Epub 2007 Oct 
      11.