L-alanosine: a noncooperative substrate for Escherichia coli aspartate transcarbamylase.
L-alanosine: a noncooperative substrate for Escherichia coli aspartate transcarbamylase.
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L-丙氨酸：大肠杆菌天冬氨酸转氨甲酰酶的非合作底物。
DOI：
10.1021/bi00346a025
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发表时间：
1985
期刊：
影响因子：
2.9
通讯作者：
G. Hervé
中科院分区：
文献类型：
--
作者：
J. Baillon;P. Tauc;G. Hervé
L-丙氨酸核苷是由丙氨酸链霉菌产生的一种抗生素，可代替L-天冬氨酸作为大肠杆菌天冬氨酸转氨甲酰酶的底物。该类似物的催化亚基的米氏常数比生理底物高约10倍，催化常数低约30倍。L-丙氨酸核苷的天然酶的饱和曲线表明利用该化合物的催化位点之间缺乏同向协同相互作用。因此，L-丙氨酸核苷似乎不能促进变构转换。然而，N-（膦酰基乙酰基）-L-天冬氨酸，一个“双底物类似物”的生理底物，刺激反应。这种现象与Foote和Lipscomb [Foote，J.，& Lipscomb，W. N.（1981）J.Biol.Chem.256，11428-11433]，涉及使用氨甲酰天冬氨酸的逆反应。该反应通常对生理效应物ATP和CTP敏感。这些结果的意义的变构调节的机制进行了讨论。
L-Alanosine, an antibiotic produced by Streptomyces alanosinicus, can be used by Escherichia coli aspartate transcarbamylase as a substrate instead of L-aspartate. The Michaelis constant of the catalytic subunit for this analogue is about 10 times higher than that for the physiological substrate, and the catalytic constant is about 30 times lower. The saturation curve of the native enzyme for L-alanosine indicates the lack of homotropic cooperative interactions between the catalytic sites for the utilization of this compound. It appears therefore that L-alanosine is unable to promote the allosteric transition. However, N-(phosphonoacetyl)-L-aspartate, a "bisubstrate analogue" of the physiological substrates, stimulates the reaction. This phenomenon is very similar to that reported by Foote and Lipscomb [Foote, J., & Lipscomb, W. N. (1981) J. Biol. Chem. 256, 11428-11433] concerning the reverse reaction using carbamylaspartate. The reaction is normally sensitive to the physiological effectors ATP and CTP. The significance of these results for the mechanism of the allosteric regulation is discussed.
天冬氨酸转氨甲酰酶的底物特异性。
DOI：
--
发表时间：
1985
期刊：
The Journal of biological chemistry
影响因子：
--
作者：
Foote,J;Lauritzen,AM;Lipscomb,WN
通讯作者：
Lipscomb,WN
大肠杆菌天冬氨酸转氨甲酰酶反向反应的动力学。
DOI：
--
发表时间：
1981
期刊：
The Journal of biological chemistry
影响因子：
--
作者：
Foote,J;Lipscomb,WN
通讯作者：
Lipscomb,WN