吲哚丙烯酸对色氨酸合成酶的抑制作用。
Inhibition of tryptophan synthetase by indoleacrylic acid.
作者信息
Matchett W H
出版信息
J Bacteriol. 1972 Apr;110(1):146-54. doi: 10.1128/jb.110.1.146-154.1972.
Indoleacrylic acid (5 x 10(-4)m in the growth medium) inhibits the growth of mycelia of Neurospora crassa and causes the cells to accumulate indoleglycerol phosphate. Measurement of kinetic parameters of partially purified tryptophan synthetase in the presence of indoleacrylic acid showed the following patterns of inhibition: in Reaction 1, the physiological reaction, indoleglycerol phosphate + serine [Formula: see text] tryptophan + glyceraldehyde-3-phosphate (unusual with respect to indoleglycerol phosphate, partially competitive with respect to serine); in Reaction 2, indole + serine [Formula: see text] tryptophan (unusual with respect to indole, partially competitive with respect to serine); in Reaction 3, indoleglycerol phosphate [Formula: see text] indole + glyceraldehyde-3-phosphate (no inhibition observed). The effects of indoleacrylic acid on whole cells were completely reversed by equimolar concentrations of tryptophan but not by indole. The addition of a 10-fold molar excess of serine to the medium completely reversed the effects. The accumulation of indoleglycerol phosphate appears to be the result of the partial blockage of tryptophan synthetase, the resulting deprivation of tryptophan, and the consequent release of its physiological feedback control on anthranilate synthetase.
吲哚丙烯酸（生长培养基中浓度为5×10⁻⁴m）抑制粗糙脉孢菌菌丝体的生长，并使细胞积累吲哚甘油磷酸。在吲哚丙烯酸存在的情况下，对部分纯化的色氨酸合成酶的动力学参数进行测量，结果显示出以下抑制模式：在反应1（生理反应）中，吲哚甘油磷酸 + 丝氨酸[公式：见原文]色氨酸 + 3-磷酸甘油醛（对吲哚甘油磷酸而言不寻常，对丝氨酸而言部分竞争性）；在反应2中，吲哚 + 丝氨酸[公式：见原文]色氨酸（对吲哚而言不寻常，对丝氨酸而言部分竞争性）；在反应3中，吲哚甘油磷酸[公式：见原文]吲哚 + 3-磷酸甘油醛（未观察到抑制作用）。吲哚丙烯酸对全细胞的影响可被等摩尔浓度的色氨酸完全逆转，但不能被吲哚逆转。向培养基中添加10倍摩尔过量的丝氨酸可完全逆转这些影响。吲哚甘油磷酸的积累似乎是色氨酸合成酶部分受阻、色氨酸缺乏以及随之而来的色氨酸对邻氨基苯甲酸合成酶的生理反馈控制解除的结果。
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