INTERACTIONS BETWEEN SUBUNITS OF TRYPTOPHAN SYNTHETASE OF ESCHERICHIA COLI . OPTICAL PROPERTITES OF AN INTERMEDIATE BOUND TO ALPHA2BETA2 COMPLEX
INTERACTIONS BETWEEN SUBUNITS OF TRYPTOPHAN SYNTHETASE OF ESCHERICHIA COLI . OPTICAL PROPERTITES OF AN INTERMEDIATE BOUND TO ALPHA2BETA2 COMPLEX
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DOI：
10.1021/bi00859a032
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发表时间：
1967-01-01
期刊：
影响因子：
2.9
通讯作者：
BALDWIN, RL
中科院分区：
文献类型：
--
作者：
GOLDBERG, ME;BALDWIN, RL
形成紧密结合的E.大肠杆菌色氨酸合成酶可以通过出现以468 m[mu]为中心的新吸收带来证明，条件是溶液除了L-丝氨酸和磷酸吡哆醛之外还含有[β]-巯基乙醇。形成的有色复合物（“琥珀复合物”）的特征在于其物理和酶性质。β-巯基乙醇的作用令人费解。它不能被尝试的其他硫醇化合物取代，并且尽管需要形成琥珀复合物，但它对于酶活性或α和β 2亚基的紧密结合并不需要。琥珀复合物的分解伴随着S-（2-羟乙基）半胱氨酸的形成，其似乎是氨基丙烯酸和巯基乙醇的加成产物。
Formation of a tightly associated a2B2 complex of E. coli tryptophan synthetase can be demonstrated by the appearance of a new absorption band centered at 468 m[mu], provided the solution contains [beta]-mercaptoethanol in addition to L-serine and pyridoxal phosphate. The colored complex which is formed ("the amber complex") has been characterized by its physical and enzymatic properties. The role of [beta]-mercaptoethanol is puzzling. It cannot be replaced by other thiol compounds tried, and although needed to form the amber complex it is not needed for enzymatic activity or for a tight association of the a and [beta]2 subunits. Break-down of the amber complex is accompanied by the formation of S-(2-hydroxyethyl)cysteine which appears to be an addition product of aminoacrylic acid and mercaptoethanol.