Department of Food Science, Whistler Center for Carbohydrate Research, Purdue University, West Lafayette, Indiana, USA.
Department of Physiological Chemistry, University of Veterinary Medicine Hannover, Hannover, Germany; and.
FASEB J. 2018 Jul;32(7):3903-3911. doi: 10.1096/fj.201701029R. Epub 2018 Feb 20.
Dietary starch is finally converted to glucose for absorption by the small intestine mucosal α-glucosidases (sucrase-isomaltase [SI] and maltase-glucoamylase), and control of this process has health implications. Here, the molecular mechanisms were analyzed associated with starch-triggered maturation and transport of SI. Biosynthetic pulse-chase in Caco-2 cells revealed that the high MW SI species (265 kDa) induced by maltose (an α-amylase starch digestion product) had a higher rate of early trafficking and maturation compared with a glucose-induced SI (245 kDa). The maltose-induced SI was found to have higher affinity to lipid rafts, which are associated with enhanced targeting to the apical membrane and higher activity. Accordingly, in situ maltose-hydrolyzing action was enhanced in the maltose-treated cells. Thus, starch digestion products at the luminal surface of small intestinal enterocytes are sensed and accelerate the intracellular processing of SI to enhance starch digestion capacity in the intestinal lumen.-Chegeni, M., Amiri, M., Nichols, B. L., Naim, H. Y., Hamaker, B. R. Dietary starch breakdown product sensing mobilizes and apically activates α-glucosidases in small intestinal enterocytes.
膳食淀粉最终通过小肠黏膜 α-葡萄糖苷酶（蔗糖异麦芽糖酶 [SI] 和麦芽糖酶-葡糖苷酶）转化为葡萄糖吸收，而对这一过程的控制与健康有关。在这里，分析了与淀粉触发的 SI 成熟和运输相关的分子机制。Caco-2 细胞中的生物合成脉冲追踪显示，麦芽糖（一种α-淀粉酶淀粉消化产物）诱导的高 MW SI 物种（265 kDa）与葡萄糖诱导的 SI（245 kDa）相比，具有更高的早期运输和成熟速率。发现麦芽糖诱导的 SI 与脂筏具有更高的亲和力，这与增强靶向顶膜和更高的活性有关。因此，在麦芽糖处理的细胞中，原位麦芽糖水解作用增强。因此，小肠上皮细胞腔表面的淀粉消化产物被感知，并加速 SI 的细胞内加工，以增强肠腔中的淀粉消化能力。-Chegeni，M.，Amiri，M.，Nichols，B. L.，Naim，H. Y.，Hamaker，B. R. 膳食淀粉分解产物感应动员并在上皮细胞中激活α-葡萄糖苷酶。
