title: Glutamate deamination by glutamate dehydrogenase plays a central role in amino acid catabolism in plants.
abstract: Glutamate is of central importance in plant N metabolism since the biosynthesis of all other amino acids requires this compound. Glutamate dehydrogenase (GDH; EC 1.4.1.2), which catalyzes in vitro reversible reductive amination of 2-oxoglutatre to form glutamate, is a key player in the metabolism of glutamate. While most previous studies have indicated that the oxidative deamination is the in vivo direction of the GDH reaction, its physiological role has remained ambiguous for decades. We have recently isolated mutants for the two known Arabidopsis GDH genes and created a gdh double mutant. Our recent work revealed an increased susceptibility of the gdh double mutant to dark-induced C starvation, the first phenotype associated with the loss of GDH activity in plants. Monitoring the amino acid breakdown during the dark treatment also suggested that the deamination of glutamate catalyzed by GDH is central to the catabolism of many other amino acids.
authors.affiliation: Department of Biological Sciences; University of Alberta; Edmonton, Alberta Canada.
authors.forename: Yo
authors.initials: Y
authors.lastname: Miyashita
authors.forename: Allen G
authors.initials: AG
authors.lastname: Good
references.citation: Plant Cell. 2006 Oct;18(10):2767-81
references.pmid: 17041150
references.citation: Plant Cell. 2006 Nov;18(11):3252-74
references.pmid: 17138698
references.citation: Plant Physiol. 1990 Oct;94(2):647-56
references.pmid: 16667761
references.citation: Plant Physiol. 2007 Dec;145(4):1726-34
references.pmid: 17932305
references.citation: Plant Physiol. 1999 Nov;121(3):687-93
references.pmid: 10557216
references.citation: Plant Cell Physiol. 2006 Mar;47(3):410-8
references.pmid: 16418233
references.citation: Planta. 2005 Sep;222(1):167-80
references.pmid: 15803323
references.citation: Plant Physiol. 2006 Feb;140(2):444-56
references.pmid: 16407450
references.citation: Plant Physiol. 1991 Sep;97(1):104-11
references.pmid: 16668355
references.citation: Planta. 2000 Sep;211(4):510-8
references.pmid: 11030550
references.citation: Proc Natl Acad Sci U S A. 1996 May 14;93(10):4718-23
references.pmid: 8643469
references.citation: J Exp Bot. 2002 Apr;53(370):979-87
references.pmid: 11912240
references.citation: Plant Physiol. 2007 Jan;143(1):530-9
references.pmid: 17114271