Yeast glyceraldehyde-3-phosphate dehydrogenase. Evidence that subunit cooperativity in catalysis can be controlled by the formation of a complex with phosphoglycerate kinase.
Yeast glyceraldehyde-3-phosphate dehydrogenase. Evidence that subunit cooperativity in catalysis can be controlled by the formation of a complex with phosphoglycerate kinase.
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酵母甘油醛-3-磷酸脱氢酶。
DOI：
10.1111/j.1432-1033.1985.tb08894.x
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发表时间：
1985
期刊：
影响因子：
--
通讯作者：
N. Nagradova
中科院分区：
文献类型：
--
作者：
L. Ashmarina;V. Muronetz;N. Nagradova
琼脂糖结合的四聚体，二聚体和单体形式的酵母甘油醛-3-磷酸脱氢酶的制备，以及固定化的杂交种含有（通过选择性氧化的活性中心半胱氨酸残基与H2 O2）一个失活的亚基每个四聚体或二聚体。这些酶形式的催化性能进行了比较，在正反应（甘油醛-3-磷酸氧化）和逆反应（1，3-bisphosphoglycerate还原脱磷酸）在稳态条件下。在甘油醛-3-磷酸氧化反应中，固定化单体和四聚体形式表现出相似的比活性。杂交修饰的二聚体贡献了天然二聚体总活性的一半。含有一个修饰亚基的四聚体具有未修饰四聚体活性的75%。在1，3-bisphosphoglycerate还原去磷酸化的反应中，单体酶种类的比活性几乎是四聚体的两倍，这表明只有一半的低聚物的活性中心同时起作用。亚基协同催化持续在一个孤立的二聚体物种。与过氧化物失活的单体在二聚体中的单体的比活性等于分离的单体物种的比活性，并且是天然固定化二聚体的比活性的两倍。与过氧化物失活的亚基在一个四聚体的亚基的比活性没有从本地固定的四聚体不同，这表明，interdimeric相互作用参与催化亚基协同。固定化甘油醛-3-磷酸脱氢酶与可溶性磷酸甘油酸激酶形成复合物。磷酸甘油酸激酶的三个单体结合每个脱氢酶的四聚体和一个二聚体。有证据表明，如果1，3-bisphosphoglycerate的还原去磷酸化在磷酸甘油酸激酶-甘油醛-3-磷酸脱氢酶复合物中进行，则后一种酶的所有活性位点独立地起作用，即亚基协同性被废除。
Sepharose-bound tetrameric, dimeric and monomeric forms of yeast glyceraldehyde-3-phosphate dehydrogenase were prepared, as well as immobilized hybrid species containing (by selective oxidation of an active center cysteine residue with H2O2) one inactivated subunit per tetramer or dimer. The catalytic properties of these enzyme forms were compared in the forward reaction (glyceraldehyde-3-phosphate oxidation) and reverse reaction (1,3-bisphosphoglycerate reductive dephosphorylation) under steady-state conditions. In the reaction of glyceraldehyde-3-phosphate oxidation, immobilized monomeric and tetrameric forms exhibited similar specific activities. The hybrid-modified dimer contributed on half of the total activity of a native dimer. The tetramer containing one modified subunit possessed 75% of the activity of an unmodified tetramer. In the reaction of 1,3-bisphosphoglycerate reductive dephosphorylation, the specific activity of the monomeric enzyme species was nearly twice as high as that of the tetramer, suggesting that only one-half of the active centers of the oligomer were acting simultaneously. Subunit cooperativity in catalysis persisted in an isolated dimeric species. The specific activity of a monomer associated with a peroxide-inactivated monomer in a dimer was equal to that of an isolated monomeric species and twice as high as that of a native immobilized dimer. The specific activity of subunits associated with a peroxide-inactivated subunit in a tetramer did not differ from that of a native immobilized tetramer; this indicates that interdimeric interactions are involved in catalytic subunit cooperativity. A complex was formed between the immobilized glyceraldehyde-3-phosphate dehydrogenase and soluble phosphoglycerate kinase. Three monomers of phosphoglycerate kinase were bound per tetramer of the dehydrogenase and one per dimer. Evidence is presented that if the reductive dephosphorylation of 1,3-bisphosphoglycerate proceeds in the phosphoglycerate kinase - glyceraldehyde-3-phosphate dehydrogenase complex, all active sites of the latter enzyme act independently, i.e. subunit cooperativity is abolished.
DOI：
--
发表时间：
1982
期刊：
The Journal of biological chemistry
影响因子：
--
作者：
Cardon,JW;Boyer,PD
通讯作者：
Boyer,PD