Human glutamate dehydrogenase is immunologically distinct from other mammalian orthologues

Jang, Sang Ho; Kim, A Yeon; Bahn, Jae Hoon; Eum, Won Sik; Kim, Dae Won; Park, Jinseu; Lee, Kil Soo; Kang, Tae‐Cheon; Won, Moo Ho; Kang, Jung Hoon; Kwon, Oh Nam; Yoon, Hae-Young; Lee, Eun-Young; Cho, Sung‐Woo; Choi, Soo Young

doi:10.1038/emm.2003.33

Cited by 2 publications

(2 citation statements)

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“…Enzyme assay and activation studies GDH activity was measured spectrophotometrically as described before (Choi et al, 1999;Jang et al, 2003) except that no ADP was added unless otherwise indicated. One unit of enzyme was defined as the amount of enzyme required to oxidize 1 mM of NADH per min at 25 o C. Stimulation studies with alkalized extracts or protopine were performed at various concentrations in assay buffer at 25 o C as described in figure legends.…”

Section: Methodsmentioning

confidence: 99%

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Regulation of glutamate level in rat brain through activation of glutamate dehydrogenase by Corydalis ternata

Lee

Huh²,

Choi³

et al. 2005

Exp Mol Med

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When treated with protopine and alkalized extracts of the tuber of Corydalis ternata for one year, significant decrease in glutamate level and increase in glutamate dehydrogenase (GDH) activity was observed in rat brains. The expression of GDH between the two groups remained unchanged as determined by Western and Northern blot analysis, suggesting a post-translational regulation of GDH activity in alkalized extracts treated rat brains. The stimulatory effects of alkalized extracts and protopine on the GDH activity was further examined in vitro with two types of human GDH isozymes, hGDH1 (house-keeping GDH) and hGDH2 (nerve-specific GDH). Alkalized extracts and protopine activated the human GDH isozymes up to 4.8-fold. hGDH2 (nervespecific GDH) was more sensitively affected by 1 mM ADP than hGDH1 (house-keeping GDH) on the activation by alkalized extracts. Studies with cassette mutagenesis at ADP-binding site showed that hGDH2 was more sensitively regulated by ADP than hGDH1 on the activation by Corydalis ternata. Our results suggest that prolonged exposure to Corydalis ternata may be one of the ways to regulate glutamate concentration in brain through the activation of GDH.

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Section: Methodsmentioning

confidence: 99%

“…The monoclonal antibodies used in this study were produced against bovine brain GDH as described before in our laboratory (Choi et al, 1999;Jang et al, 2003). For the isolation of RNA, five volumes of 4M guanidinium thiocyanate buffer were added to brains and homogenized with a Polytron homogenizer.…”

Section: Northern and Western Blotsmentioning

confidence: 99%

Regulation of glutamate level in rat brain through activation of glutamate dehydrogenase by Corydalis ternata

Lee

Huh²,

Choi³

et al. 2005

Exp Mol Med

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Amino Acid Changes within Antenna Helix Are Responsible for Different Regulatory Preferences of Human Glutamate Dehydrogenase Isozymes

Choi

Kim

Yang

et al. 2007

Journal of Biological Chemistry

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Human glutamate dehydrogenase (hGDH) exists in hGDH1 (housekeeping isozyme) and in hGDH2 (nerve-specific isozyme), which differ markedly in their allosteric regulation. Because they differ in only 16 of their 505 amino acids, the regulatory preferences must arise from amino acid residues that are not common between hGDH1 and hGDH2. To our knowledge none of the mutagenesis studies on the hGDH isozymes to date have identified the amino acid residues fully responsible for the different regulatory preferences between hGDH1 and hGDH2. In this study we constructed hGDH1(hGDH2 390 -448 )hGDH1 (amino acid segment 390 -448 of hGDH1 replaced by the corresponding hGDH2 segment) and hGDH2(hGDH1 390 -448 )hGDH2 (amino acid segment 390 -448 of hGDH2 replaced by the corresponding hGDH1 segment) by swapping the corresponding amino acid segments in hGDH1 and hGDH2. The chimeric enzymes by reciprocal swapping resulted in double mutations in amino acid sequences at 415 and 443 residues that are not common between hGDH1 and hGDH2 and are located in the C-terminal 48-residue "antenna" helix, which is thought to be part of the regulatory domain of mammalian GDHs. Functional analyses revealed that the doubly mutated chimeric enzymes almost completely acquired most of the different regulatory preferences between hGDH1 and hGDH2 for electrophoretic mobility, heat-stability, ADP activation, palmitoyl-CoA inhibition, and L-leucine activation, except for GTP inhibition. Our results indicate that substitutions of the residues in the antenna region may be important evolutionary changes that led to the adaptation of hGDH2 to the unique metabolic needs of the nerve tissue.

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Human glutamate dehydrogenase is immunologically distinct from other mammalian orthologues

Abstract: A bstract

Cited by 2 publications

References 30 publications

Regulation of glutamate level in rat brain through activation of glutamate dehydrogenase by Corydalis ternata

Regulation of glutamate level in rat brain through activation of glutamate dehydrogenase by Corydalis ternata

Amino Acid Changes within Antenna Helix Are Responsible for Different Regulatory Preferences of Human Glutamate Dehydrogenase Isozymes

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