Amino-Acid Sequence of Sperm Whale Myoglobin
Amino-Acid Sequence of Sperm Whale Myoglobin
复制标题
抹香鲸肌红蛋白的氨基酸序列
DOI：
10.1038/205883a0
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发表时间：
1965
期刊：
影响因子：
64.8
通讯作者：
Edmundson Ab
中科院分区：
文献类型：
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作者：
Edmundson Ab
将细胞在含有所有营养物（如前所述）但不含葡萄糖的肉汤中保持15小时后，在发酵试验的前2小时内，它们不能发酵松二糖、麦芽糖或蔗糖，并且在4小时内仍然不能发酵α-甲基葡萄糖和三聚果糖（图3B）。然而，当葡萄糖生长的细胞保持在磷酸盐缓冲液（pH 4-5）含有2%的葡萄糖，为15小时，酶的活性得到维持，揭示了，在这个特定的突变体中，enzitase都是由葡萄糖诱导和维持的。葡萄糖对enzitase的诱导表明，在指定的酶是“组成型”的不确定性。如果诱导物是细胞中常见的且持续存在的成分，则诱导酶会被误认为是“组成型”酶。通过酶活性的“终产物”之一对酶的诱导与通过酶的活性的“终产物”控制酶的概念相矛盾。
After the cells were held for 15 h in a broth contain-ing all nutrients (described previously) but without glucose, they were unable to ferment either turanose, maltose or sucrose during the first 2 h in the fermentation test, and remained unable to ferment alpha-methylglucose and melezitose for 4 h (Fig. 3B). However, when the glucose-grown cells were held in phosphate buffer (pH 4-5) containing 2 per cent of glucose, for 15 h, the enzyme activity was maintained, revealing that melezitase was both induced and maintained by glucose in this particular mutant.The induction of melezitase by glucose demonstrates the indeterminacy involved in specifying that an enzyme is “constitutive". If the inductor is a common and con-stantly present component of the cell, an inducible enzyme would be mistaken for a “constitutive” enzyme"". The induction of an enzyme by one of the “end-products' of its activity is contradictory to the concept of control by