II. Physiologisches Institut der Universität des Saarlandes, Homburg (Saar), Germany.
J Membr Biol. 1971 Dec;4(1):270-83. doi: 10.1007/BF02431975.
Using(14)C-erythritol, we measured net as well as unidirectional erythritol fluxes. Up to near saturation, net and unidirectional fluxes were virtually identical and linearly related to the erythritol concentration in the medium (isotonic saline). No saturation of the transfer system was observed. At 20°C, a maximum of 60 to 70% of the erythritol flux could be inhibited by glucose, phlorizin, or a combination of both substances. Dinitrofluorobenzene and HgCl2 also reduce erythritol permeability. These findings confirm the earlier conclusion of F. Bowyer and W. F. Widdas that the glucose transport system is involved in erythritol permeation. Glycerol partially inhibits the glucose-phlorizin-sensitive component of erythritol flux, but not the glucose-phlorizin-insensitive component. Apparently glycerol has a slight affinity to that portion of the glucose transport system which is involved in erythritol transfer, whereas the glucosephlorizin-insensitive fraction of erythritol movements is not identical with the glycerol system. This latter inference is supported by the observation that, in contrast to glycerol permeability, erythritol permeability is insensitive to variations of pH or to the addition of copper. The apparent activation energy of the glucose-phlorizin-sensitive and-insensitive fractions of erythritol permeation are 22.2 and 20.7 kcal/mole, respectively. These values are not significantly different from one another.
利用(14)C-赤藓糖醇，我们测量了净和单向赤藓糖醇通量。在接近饱和之前，净通量和单向通量几乎相同，并且与介质（等渗盐水）中的赤藓糖醇浓度呈线性相关。未观察到传递系统的饱和。在 20°C 下，葡萄糖、根皮苷或两者的组合最多可抑制 60%至 70%的赤藓糖醇通量。二硝基氟苯和 HgCl2 也降低了赤藓糖醇的通透性。这些发现证实了 F. Bowyer 和 W. F. Widdas 的早期结论，即葡萄糖转运系统参与了赤藓糖醇的渗透。甘油部分抑制了赤藓糖醇通量中对葡萄糖-根皮苷敏感的成分，但不抑制葡萄糖-根皮苷不敏感的成分。显然，甘油对参与赤藓糖醇转移的葡萄糖转运系统的那部分有轻微的亲和力，而赤藓糖醇运动中对葡萄糖-根皮苷不敏感的部分与甘油系统并不相同。这后一种推断得到了以下观察结果的支持：与甘油通透性不同，赤藓糖醇通透性对 pH 值的变化或添加铜不敏感。葡萄糖-根皮苷敏感和不敏感的赤藓糖醇渗透部分的表观活化能分别为 22.2 和 20.7 kcal/mol。这些值彼此之间没有显著差异。
