Muraoka A, Ito K, Nagasaki H, Tanaka S
Department of Medical Technology, Kochi Gakuen College.
Nihon Saikingaku Zasshi. 1991 Mar;46(2):515-22. doi: 10.3412/jsb.46.515.
A wild-type strain of Enterococcus faecalis and its mutants resistant to 2-deoxy-D-glucose (2DG) were examined for the presence of phosphoenolpyruvate:carbohydrate phosphotransferase systems (PTSs) with 12 carbohydrates, which were utilized by the organism, as the substrates. The wild-type strain possessed a constitutive mannose-PTS, which was reactive with glucose, mannose, glucosamine, 2DG and fructose. This activity was absent in the mutants. No independent glucose- or fructose-PTS was found in the mannose-PTS-defective mutants. The mutants, however, showed a low level of a constitutive PTS activity with maltose, suggesting the existence of an independent maltose-PTS in the organism. Both wild-type and mutant strains possessed inducible lactose-, mannitol-, and trehalose-PTSs. Lactose-PTS was induced by either lactose or galactose in the parent, but only by lactose in the mutants. The lactose-PTS was not reactive with galactose, and no separate galactose-PTS was present. These observations suggest that the inducer for lactose-PTS, probably being galactose 6-phosphate, may not be formed from galactose in the organism when the constitutive mannose-PTS is lost by mutation.
对粪肠球菌的野生型菌株及其对2-脱氧-D-葡萄糖（2DG）耐药的突变体进行了检测，以12种该生物体可利用的碳水化合物作为底物，检测磷酸烯醇丙酮酸：碳水化合物磷酸转移酶系统（PTSs）的存在情况。野生型菌株拥有组成型甘露糖-PTS，其对葡萄糖、甘露糖、氨基葡萄糖、2DG和果糖有反应。在突变体中不存在这种活性。在甘露糖-PTS缺陷型突变体中未发现独立的葡萄糖-或果糖-PTS。然而，这些突变体显示出对麦芽糖有低水平的组成型PTS活性，表明该生物体中存在独立的麦芽糖-PTS。野生型和突变型菌株均拥有可诱导的乳糖-、甘露醇-和海藻糖-PTSs。亲本中的乳糖-PTS可由乳糖或半乳糖诱导，但在突变体中仅由乳糖诱导。乳糖-PTS对半乳糖无反应，且不存在单独的半乳糖-PTS。这些观察结果表明，当组成型甘露糖-PTS因突变而缺失时，乳糖-PTS的诱导剂（可能是6-磷酸半乳糖）可能无法在生物体中由半乳糖形成。
