Hanke D W, Warden D A, Evans J O, Fannin F F, Diedrich D F
Biochim Biophys Acta. 1980 Jul;599(2):652-63. doi: 10.1016/0005-2736(80)90207-2.
Phlorizin, labeled with tritium only in the glucose moiety, was used as substrate for the beta-glucosidase present in brush border membranes from hamster intestine in order to study, simultaneously, the kinetics of hydrolysis and the fate of the [3H]glucose liberated by the enzyme. The [3H]glucose seems to experience the same hydrolase related transport into the intestinal villi as the hexoses liberated from the common disaccharides byu their respective hydrolases. The released [3H]glucose accumulation rate is only partially inhibited by unlabelled glucose added to the medium as either the free sugar or as the precursors sucrose, lactose or glucose 1-phosphate, and then only when these sugars are present at very high levels. Furthermore, glucose oxidase, added to the medium as a glucose scavenger, has no effect on the uptake rate of the phlorizin hydrolase-liberated sugar. These and other findings are presented as evidence that, under conditions where the Na+-dependent glucose carrier is more than 97% inhibited by phlorizin, the glucose derived from the inhibitor, like the hexoses from disaccharides, has a kinetic advantage for transfer into the intestinal tissue.
仅在葡萄糖部分用氚标记的根皮苷被用作仓鼠肠道刷状缘膜中存在的β-葡萄糖苷酶的底物，以便同时研究水解动力学和该酶释放的[3H]葡萄糖的去向。[3H]葡萄糖似乎与由各自水解酶从常见二糖释放的己糖经历相同的与水解酶相关的向肠绒毛的转运。释放的[3H]葡萄糖积累速率仅在作为游离糖或作为前体蔗糖、乳糖或葡萄糖1-磷酸添加到培养基中的未标记葡萄糖存在时才受到部分抑制，而且只有当这些糖以非常高的水平存在时才会如此。此外，作为葡萄糖清除剂添加到培养基中的葡萄糖氧化酶对根皮苷水解酶释放的糖的摄取速率没有影响。这些发现以及其他发现表明，在根皮苷对钠依赖性葡萄糖载体的抑制率超过97%的条件下，抑制剂衍生的葡萄糖与二糖中的己糖一样，在转运到肠道组织方面具有动力学优势。
