Barber A, Cemborain E, de la Pisa J, Ponz F
Rev Esp Fisiol. 1985 Dec;41(4):423-9.
The net entry of galactose into the tissue of snail everted intestinal rings with 2 or 15 minute long incubation periods has been measured. With 10(-4) M phlorizin, the mediated transport is completely blocked while only the passive entry of sugar is produced. Lower concentrations of the glycoside partially inhibit transport according to competitive inhibition kinetics (K1 = 10(-7) M). The transport of galactose is Na+ dependent. In the absence of Na+, transport ceases and the sugar entry can be explained through simple diffusion. With 15 mM Na+ (control 71,4 mM) transport diminishes and a marked increase in the apparent Km with no changes in the Vmax is observed. One mM harmaline completely blocks galactose (0.5 mM) transport. One mM ouabain also makes transport null, but only after tissue preincubation with the inhibitor on the serosal side.
已测量了在2分钟或15分钟孵育期内半乳糖进入蜗牛外翻肠环组织的净通量。使用10⁻⁴M根皮苷时，介导转运被完全阻断，仅产生糖的被动进入。较低浓度的糖苷根据竞争性抑制动力学（K1 = 10⁻⁷M）部分抑制转运。半乳糖的转运依赖于Na⁺。在没有Na⁺的情况下，转运停止，糖的进入可以通过简单扩散来解释。使用含15mM Na⁺（对照为71.4mM）时，转运减少，观察到表观Km显著增加而Vmax无变化。1mM骆驼蓬碱完全阻断半乳糖（0.5mM）的转运。1mM哇巴因也使转运消失，但仅在组织在浆膜侧用抑制剂预孵育后才会出现这种情况。
