Insights into the in vivo regulation of glutamate dehydrogenase from the foot muscle of an estivating land snail.
Insights into the in vivo regulation of glutamate dehydrogenase from the foot muscle of an estivating land snail.
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DOI：
10.1155/2012/317314
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发表时间：
2012
期刊：
影响因子：
--
通讯作者：
Storey KB
中科院分区：
文献类型：
--
作者：
Bell RA;Dawson NJ;Storey KB
陆地蜗牛（Otalalactea）通过进入一种称为夏眠的有氧休眠状态，在季节性炎热和干燥的环境中生存。在夏眠期间，蜗牛必须防止过度脱水并重新组织代谢燃料的使用，以便忍受长时间没有食物的情况。据推测，谷氨酸脱氢酶 (GDH) 在夏眠期间发挥着关键作用，因为它将氨基酸碳骨架穿梭到克雷布斯循环中以产生能量，并且对于尿素生物合成（用于保水的关键分子）非常重要。对对照和夏眠条件下纯化的足部肌肉 GDH 的分析表明，与对照相比，夏眠 GDH 在催化谷氨酸脱氨基作用方面的活性大约高 3 倍。正如 ProQ Diamond 磷蛋白染色和刺激内源蛋白激酶和磷酸酶的孵育所表明的那样，这种动力学差异似乎受到可逆蛋白磷酸化的调节。在夏眠的陆地蜗牛足部肌肉中观察到的高磷酸盐形式的 GDH 活性增加，与长时间夏眠期间增加的能量氨基酸使用和用于保持水分的尿素合成增加密切相关。
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.