Mechanism of allosteric regulation of the Ca,Mg-ATPase of sarcoplasmic reticulum: studies with 5'-adenylyl methylenediphosphate.
Mechanism of allosteric regulation of the Ca,Mg-ATPase of sarcoplasmic reticulum: studies with 5'-adenylyl methylenediphosphate.
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肌浆网 Ca,Mg-ATP 酶变构调节机制：5-腺苷酸亚甲基二磷酸的研究。
DOI：
10.1021/bi00341a049
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发表时间：
1985
期刊：
影响因子：
2.9
通讯作者：
F. Briggs
中科院分区：
文献类型：
--
作者：
M. Cable;J. Feher;F. Briggs
Four mechanisms for the allosteric regulation of the calcium and magnesium ion activated adenosinetriphosphatase (Ca,Mg-ATPase) of sarcoplasmic reticulum were examined. Negative cooperativity in substrate binding was not supported by 3H-labeled 5'-adenylyl methylenediphosphate (AMPPCP) binding, which was best fit by a single class of sites. Although calcium had no effect on the absence of cooperativity, it did increase the affinity of the enzyme for AMPPCP. Allosteric regulation via an effector site for AMPPCP or ATP on the same ATPase chain was eliminated by the stoichiometry of ATP and AMPPCP binding, 1 mol of site per mole of enzyme. The possibility that AMPPCP acts at an effector site was eliminated by showing that it competitively inhibits the rate of phosphoenzyme formation. Allosteric regulation of kinetics via site-site interaction in an oligomer was eliminated by showing that the inhibition of ATPase activity by fluorescein isothiocyanate is linearly dependent upon its incorporation into the sarcoplasmic reticulum. The fourth mechanism considered was stimulation of ATPase activity by the binding of ATP or AMPPCP at the active site after departure of ADP but before the departure of inorganic phosphate. This hypothesis was supported by site stoichiometry and by the observation that AMPPCP or ATP stimulates v/EP, the rate of ATP hydrolysis for a given level of phosphoenzyme. Computer simulation of this branched monomeric model could duplicate all experimental observations made with AMPPCP and ATP as allosteric regulators. The condition that the affinity of ATP binding to the enzyme be reduced when it is phosphorylated, which is required by the computer model, was confirmed experimentally.
影响因子：
18.2
作者：
N. Ikemoto
通讯作者：
N. Ikemoto
研究 2,3-O-(2,4,6-三硝基环己基二烯基) 腺苷核苷酸与肌浆网 (Ca2 Mg2 )-ATP 酶活性位点的相互作用。
DOI：
--
发表时间：
1984
期刊：
The Journal of biological chemistry
影响因子：
--
作者：
Nakamoto,RK;Inesi,G
通讯作者：
Inesi,G
钙转运 ATP 酶的能量。
DOI：
--
发表时间：
1984
期刊：
The Journal of biological chemistry
影响因子：
--
作者：
Pickart,CM;Jencks,WP
通讯作者：
Jencks,WP