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Insights into the in vivo regulation of glutamate dehydrogenase from the foot muscle of an estivating land snail.

Bell RA, Dawson NJ, Storey KB - Enzyme Res (2012)

Bottom Line: Glutamate dehydrogenase (GDH) was hypothesized to play a key role during estivation as it shuttles amino acid carbon skeletons into the Krebs cycle for energy production and is very important to urea biosynthesis (a key molecule used for water retention).This kinetic difference appears to be regulated by reversible protein phosphorylation, as indicated by ProQ Diamond phosphoprotein staining and incubations that stimulate endogenous protein kinases and phosphatases.The increased activity of the high-phosphate form of GDH seen in the estivating land snail foot muscle correlates well with the increased use of amino acids for energy and increased synthesis of urea for water retention during prolonged estivation.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemistry, Carleton University, 1125 Colonel By Drive, Ottawa, ON, Canada K1S 5B6.

ABSTRACT
Land snails, Otala lactea, survive in seasonally hot and dry environments by entering a state of aerobic torpor called estivation. During estivation, snails must prevent excessive dehydration and reorganize metabolic fuel use so as to endure prolonged periods without food. Glutamate dehydrogenase (GDH) was hypothesized to play a key role during estivation as it shuttles amino acid carbon skeletons into the Krebs cycle for energy production and is very important to urea biosynthesis (a key molecule used for water retention). Analysis of purified foot muscle GDH from control and estivating conditions revealed that estivated GDH was approximately 3-fold more active in catalyzing glutamate deamination as compared to control. This kinetic difference appears to be regulated by reversible protein phosphorylation, as indicated by ProQ Diamond phosphoprotein staining and incubations that stimulate endogenous protein kinases and phosphatases. The increased activity of the high-phosphate form of GDH seen in the estivating land snail foot muscle correlates well with the increased use of amino acids for energy and increased synthesis of urea for water retention during prolonged estivation.

No MeSH data available.


Related in: MedlinePlus

Purified control Otala lactea foot muscle GDH. The silver-stained gel displays the following: lane 1: Thermo Scientific Fermentas protein ladder with the molecular weight (kDa) of key bands indicated to the left of the lane; lane 2: bovine liver GDH (Sigma); lane 3: purified control land snail GDH.
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fig1: Purified control Otala lactea foot muscle GDH. The silver-stained gel displays the following: lane 1: Thermo Scientific Fermentas protein ladder with the molecular weight (kDa) of key bands indicated to the left of the lane; lane 2: bovine liver GDH (Sigma); lane 3: purified control land snail GDH.

Mentions: GDH was purified to electrophoretic homogeneity (Figure 1) using a GTP-agarose affinity column. This one step purification isolated GDH with a yield of 64% and a fold purification of 2000 (Table 1). GDH was stable for more than 48 hr (stored at 4°C) following purification without appreciable loss of activity (data not shown).


Insights into the in vivo regulation of glutamate dehydrogenase from the foot muscle of an estivating land snail.

Bell RA, Dawson NJ, Storey KB - Enzyme Res (2012)

Purified control Otala lactea foot muscle GDH. The silver-stained gel displays the following: lane 1: Thermo Scientific Fermentas protein ladder with the molecular weight (kDa) of key bands indicated to the left of the lane; lane 2: bovine liver GDH (Sigma); lane 3: purified control land snail GDH.
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3318891&req=5

fig1: Purified control Otala lactea foot muscle GDH. The silver-stained gel displays the following: lane 1: Thermo Scientific Fermentas protein ladder with the molecular weight (kDa) of key bands indicated to the left of the lane; lane 2: bovine liver GDH (Sigma); lane 3: purified control land snail GDH.
Mentions: GDH was purified to electrophoretic homogeneity (Figure 1) using a GTP-agarose affinity column. This one step purification isolated GDH with a yield of 64% and a fold purification of 2000 (Table 1). GDH was stable for more than 48 hr (stored at 4°C) following purification without appreciable loss of activity (data not shown).

Bottom Line: Glutamate dehydrogenase (GDH) was hypothesized to play a key role during estivation as it shuttles amino acid carbon skeletons into the Krebs cycle for energy production and is very important to urea biosynthesis (a key molecule used for water retention).This kinetic difference appears to be regulated by reversible protein phosphorylation, as indicated by ProQ Diamond phosphoprotein staining and incubations that stimulate endogenous protein kinases and phosphatases.The increased activity of the high-phosphate form of GDH seen in the estivating land snail foot muscle correlates well with the increased use of amino acids for energy and increased synthesis of urea for water retention during prolonged estivation.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemistry, Carleton University, 1125 Colonel By Drive, Ottawa, ON, Canada K1S 5B6.

ABSTRACT
Land snails, Otala lactea, survive in seasonally hot and dry environments by entering a state of aerobic torpor called estivation. During estivation, snails must prevent excessive dehydration and reorganize metabolic fuel use so as to endure prolonged periods without food. Glutamate dehydrogenase (GDH) was hypothesized to play a key role during estivation as it shuttles amino acid carbon skeletons into the Krebs cycle for energy production and is very important to urea biosynthesis (a key molecule used for water retention). Analysis of purified foot muscle GDH from control and estivating conditions revealed that estivated GDH was approximately 3-fold more active in catalyzing glutamate deamination as compared to control. This kinetic difference appears to be regulated by reversible protein phosphorylation, as indicated by ProQ Diamond phosphoprotein staining and incubations that stimulate endogenous protein kinases and phosphatases. The increased activity of the high-phosphate form of GDH seen in the estivating land snail foot muscle correlates well with the increased use of amino acids for energy and increased synthesis of urea for water retention during prolonged estivation.

No MeSH data available.


Related in: MedlinePlus