Regulation of bovine glutamate dehydrogenase. The effects of pH and ADP.
Regulation of bovine glutamate dehydrogenase. The effects of pH and ADP.
复制标题
牛谷氨酸脱氢酶的调节。
DOI：
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发表时间：
1982
影响因子：
4.8
通讯作者：
J. E. Bell
中科院分区：
文献类型：
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作者：
J. Bailey;E. Bell;J. E. Bell
牛肝谷氨酸脱氢酶的活性受到底物浓度和ph的多种影响。在ph 6.5及以下，氧化脱氨和还原性胺化反应均被ADP抑制。在pH 7.0及以上时，根据底物浓度的不同，可以观察到激活和抑制作用。这种效应可以用ADP在调控位点结合并在活性位点与辅酶竞争的模型来解释。ADP的激活作用是由于ADP结合其调控位点使各种失活复合物失稳。pH和ADP的协同作用导致激活效应或抑制效应的增强，这取决于条件。考虑到体内各种底物的浓度、线粒体内pH值和腺嘌呤核苷酸水平，表明体内还原性胺化反应更有利。这表明谷氨酸脱氢酶可能通过响应线粒体氨水平的变化密切参与尿素循环的调节。
The activity of bovine liver glutamate dehydrogenase is affected in several ways depending on substrate concentrations and pH. At ph 6.5 and below, both oxidative deamination and reductive amination reactions are inhibited by ADP. At pH 7.0 and above both activatory and inhibitory effects can be observed depending on substrate concentrations. The effects are explicable in terms of a model with ADP binding at both a regulatory site and competing with coenzyme at the active site. The activatory effects of ADP result from destabilization of various abortive complexes by ADP binding to its regulatory site. The concerted effects of pH and ADP lead to a potentiation of either activation effects or inhibition effects depending on conditions. A consideration of in vivo concentrations of the various substrates involved and intramitochondrial pH and adenine nucleotide levels suggests that in vivo the reductive amination reaction is favored. It is suggested that glutamate dehydrogenase may be intimately involved with regulation of the urea cycle by responding to changes in the mitochondrial ammonia levels.