大肠杆菌破碎原生质球中β-半乳糖苷酶的诱导合成
Inducible synthesis of beta-galactosidase in disrupted spheroplast of Escherichia coli.
作者信息
Maruo B, Seto H, Nagata Y
出版信息
J Bacteriol. 1969 Oct;100(1):209-14. doi: 10.1128/jb.100.1.209-214.1969.
A membrane preparation obtained from osmotic lysate of spheroplasts of Escherichia coli cells showed an activity of synthesizing beta-galactosidase which was dependent upon oxidative phosphorylation. The synthesis was inhibited by the addition of actinomycin D or of chloramphenicol. The beta-galactosidase synthesized in the membrane preparation was completely released into the medium, while that synthesized in the spheroplasts and intact cells remained within the cells. The minimum concentration of the inducer, methyl-beta-d-thiogalactoside, required for the induction of beta-galactosidase was 5 x 10(-5)m for intact cells, 3 x 10(-4)m for spheroplasts and 1 x 10(-3)m for membrane preparation. Incorporation of labeled glucose into insoluble components in membrane preparation was extremely low compared with that in intact cells or in spheroplasts. Based on these and other observations, the nature of this membrane preparation is discussed in relation to the structure of E. coli cells.
从大肠杆菌细胞原生质球的渗透裂解物中获得的膜制剂显示出合成β-半乳糖苷酶的活性，该活性依赖于氧化磷酸化。放线菌素D或氯霉素的添加会抑制该合成过程。在膜制剂中合成的β-半乳糖苷酶会完全释放到培养基中，而在原生质球和完整细胞中合成的β-半乳糖苷酶则保留在细胞内。诱导β-半乳糖苷酶所需的诱导剂甲基-β-D-硫代半乳糖苷的最低浓度，完整细胞为5×10⁻⁵m，原生质球为3×10⁻⁴m，膜制剂为1×10⁻³m。与完整细胞或原生质球相比，膜制剂中标记葡萄糖掺入不溶性成分的比例极低。基于这些及其他观察结果，结合大肠杆菌细胞的结构对该膜制剂的性质进行了讨论。
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