Rosiers C, Verwaerde F, Dupas H, Bouquelet S
Ann Nutr Metab. 1985;29(2):76-82. doi: 10.1159/000176964.
The maltase (EC 3.2.1.20)/glucoamylase (EC 3.2.1.3) complex from rat small intestine brush border, which is able to split alpha (1----4) glucose-sorbitol linkage, was isolated and purified by chromatography on DEAE-Trisacryl M and Sepharose 6B. The complex was homogeneous on polyacrylamide gel electrophoresis. Kinetic parameters were studied on two substrates: maltose and maltitol (Km:1.3 mM and 30 mM, Vmax:200 nmol X min-1 and 15 nmol X min-1, respectively). Inhibition studies were performed with maltose and maltitol as substrates and isomaltitol and delta-gluconolactone as inhibitors. Crossed-inhibition reactions were also performed. The results support the existence of one single catalytic site and this fact was confirmed by physicochemical properties. Similar results were obtained with germ-free rats as well as with conventional rats adapted over 6-12 months to Lycasin 80/55 as the sole source of sugar. Lycasin 80/55, hydrogenated starch hydrolysate, was converted by purified maltase/glucoamylase complex in glucose and sorbitol.
从大鼠小肠刷状缘分离纯化出一种麦芽糖酶（EC 3.2.1.2）/葡糖淀粉酶（EC 3.2.1.3）复合物，该复合物能够裂解α(1→4)葡萄糖 - 山梨醇键，通过在DEAE - Trisacryl M和琼脂糖凝胶6B上进行色谱分离实现。该复合物在聚丙烯酰胺凝胶电泳上呈现均一性。研究了其对两种底物麦芽糖和麦芽糖醇的动力学参数（Km：分别为1.3 mM和30 mM，Vmax：分别为200 nmol·min⁻¹和15 nmol·min⁻¹）。以麦芽糖和麦芽糖醇为底物，异麦芽糖醇和δ - 葡糖酸内酯为抑制剂进行抑制研究。还进行了交叉抑制反应。结果支持存在单一催化位点，这一事实通过物理化学性质得到证实。无菌大鼠以及适应6 - 12个月以Lycasin 80/55作为唯一糖源的普通大鼠也得到了类似结果。Lycasin 80/55，即氢化淀粉水解物，被纯化的麦芽糖酶/葡糖淀粉酶复合物转化为葡萄糖和山梨醇。
