Freiburghaus A U, Dubs R, Hadorn B, Gaze H, Hauri H P, Gitzelmann R
Eur J Clin Invest. 1977 Oct;7(5):455-9. doi: 10.1111/j.1365-2362.1977.tb01634.x.
In a child with hereditary sucrase-isomaltase deficiency immunoreactive enzyme was present in the intact duodenal mucosa. Polyacrylamide gel electrophoresis carried out with membrane fragments of an intestinal biopsy showed an abnormal protein band without enzyme activity. The mucosa had a relatively high residual isomaltase activity which was recovered from the gel in a position suggesting higher than normal molecular weight. The results indicated that in this patient the primary structural defect was in the sucrase moiety which was enzymatically inactive. The isomaltase subunits may have aggregated into a large molecular weight complex because of unavailability of their partners. The observation also provided evidence for separate biosynthesis of the two moieties of the sucrase-isomaltase complex.
在一名患有遗传性蔗糖酶-异麦芽糖酶缺乏症的儿童中，完整的十二指肠黏膜中存在免疫反应性酶。对肠道活检的膜片段进行的聚丙烯酰胺凝胶电泳显示出一条无酶活性的异常蛋白带。黏膜具有相对较高的残余异麦芽糖酶活性，该活性从凝胶中回收时所处位置表明分子量高于正常水平。结果表明，在该患者中，主要的结构缺陷在于无酶活性的蔗糖酶部分。由于缺乏其配对亚基，异麦芽糖酶亚基可能聚合成了一种大分子复合物。该观察结果也为蔗糖酶-异麦芽糖酶复合物的两个部分是分别生物合成的这一观点提供了证据。
