FUNGAL GLUCOAMYLASE SUPPLEMENTS ON STARCH DIGESTION IN GLUCOSIDASE DEFICIENT

真菌葡糖淀粉酶补充葡萄糖苷酶缺乏症中的淀粉消化

• 批准号: 8356720
• 负责人: Mark Alan Gilger
• 金额: $ 0.44万
• 依托单位: BAYLOR COLLEGE OF MEDICINE
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-12-01 至 2011-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8356720
• 关键词: Alpha-glucosidase; Amylases; Amylopectin; Assimilations; Binding; Biological Assay; Biopsy; Brush Border; Carbohydrates; Child; Clinical; Clinical Research; Colon; Complex; Dextrins; Diarrhea; Digestion; Disaccharidases; Energy Intake; Enzymes; Failure; Failure to Thrive; Family; Food; Funding; Gases; Generic Drugs; Genes; Genomics; Glucan 1,4-alpha-Glucosidase; Glucose; Glycogen; Grant; Human; Immunoprecipitation; Individual; Inherited; Intestines; Lactase; Length; Maltose; Membrane; Monosaccharides; Mucous Membrane; National Center for Research Resources; Oligo-1,6-Glucosidase; Oligosaccharides; Oral; Pancreas; Paper; Pattern; Peptides; Principal Investigator; Proteins; Proteomics; Protocols documentation; Reporting; Research; Research Infrastructure; Resources; Role; Salivary; Sampling; Secondary to; Siblings; Small Intestines; Source; Starch; Subgroup; Substrate Specificity; Sucrase; Symptoms; Syndrome; United States National Institutes of Health; Writing; absorption; aged; alpha-amylase; clinical Diagnosis; congenital sucrose isomaltose malabsorption; cost; dextrin; dietary restriction; enzyme therapy; glucose production; glucosidase; jejunum; sucrase-isomaltase-maltase; sugar

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. ABSTRACT Starches and sugars make up 60-90% of human dietary energy intakes. All food carbohydrates (CHO)s are digested in the small intestine to monosaccharides before absorption by a family of membrane bound luminal enzymes called disaccharidases. The best studied disaccharidases are lactase, and sucrase-isomaltase. Because of recognizable clinical symptoms, congenital sucrase-isomaltase deficiencies (CSID) have been studied at clinical, proteomic and genomic levels. While the role of salivary and pancreatic alpha-amylase activities in starch digestion are well known, the roles of mucosal alpha-glucosidases activities are less understood. Alpha-amylases release only 4% of the glucose present in amylopectin. The remaining 96% of products are soluble glucose oligomers with a conserved pattern of lengths. These oligomers, including maltose (G2) and lengths through G40 require further digestion. Mucosal glucosidases release free glucose from the non-reducing ends of the soluble oligomers. Differentiation of amylase from glucosidases activity was first reported in 1880 after discovery of maltase activity in small intestine and its absence in the pancreas. In the 1960s Dahlqvist found that 4 different maltase activities could be identified in the human jejunum; two were isolated with sucrase-isomaltase (SI) activities and two, that were free of all other disaccharidase activities, were called maltase-glucoamylase (MGAM). In the 1980s Hermann, et al. proved that mucosal maltase activities are a subgroup of the glucosidases and that while substrate specificities of SI and MGAM are identical, the activity of MGAM was 100 fold greater and the concentration of SI peptide is 20 fold greater. This dictates that both must be investigated to understand mucosal glucose production from food starches. This protocol is a generic version of H-20932 which was written for a family with hereditary poor starch digestion. In this protocol we will study a national sample of children with similar low duodenal biopsy maltase and normal sucrase activities. The impetus for this study relates to two young siblings with failure-to-thrive that is believed to be secondary to starch intolerance. They have sought treatment for this condition that is currently managed by dietary restrictions (see H-20932). In the older child the condition has been attributed to biopsy-proven, congenital absence of the intestinal brush border enzyme called maltase. The glucosidase activities for the biopsy were, sucrase 40.6 (nl 25), maltase 87.1 (nl 100), and palatinase 6.8 (nl 5). All values were uM/min/g protein. Glucosidase enzymes reduce oligosaccharides to simple glucose that can be absorbed into the body. Failure results in undigested complex carbohydrates that pass to the colon and provoke gas, bloating, irritability and diarrhea. A similar syndrome was described by Lebenthal in 1994, nine children aged from 6-107 months were found to have clinical starch intolerance. Lebenthal used glycogen as substrate for a mucosal biopsy glucosidase assay and reported that deficient activity generally agreed with his clinical diagnosis. We now know that glycogen substrate is only about 80% specific for the MGAM activity of the mucosa. In the 14 years since Lebenthals paper we have shown that four glucosidases participate in the post-amylase digestion of oligosaccharides to glucose and that specific substrates cannot dissect these glucosidase activities. We have found that immunoprecipitation of the activities can resolve individual contributions by the different genes to starch digestion. HYPOTHESIS Supplemental oral enzyme therapy, containing fungal amyloglucosidase, will be beneficial to symptomatic children with congenital maltase glucoamylase deficiency as shown by symptom improvement and increased breath sample enrichment values (objective surrogate of brush border alpha-limit-dextrin digestion and product assimilation) . I. SPECIFIC AIMS 1. To demonstrate that supplemental oral enzyme therapy, containing fungal amyloglucosidase, is beneficial to symptomatic children with congenital maltase glucoamylase deficiency. 2. To demonstrate symptom improvement 3. To demonstrate increased breath sample enrichment values (objective surrogate of brush border alpha-limit-dextrin digestion and product assimilation)

这个子项目是许多利用资源的研究子项目之一 由NIH/NCRR资助的中心拨款提供。子项目的主要支持 而子项目的主要调查员可能是由其他来源提供的， 包括其他NIH来源。 列出的子项目总成本可能 代表子项目使用的中心基础设施的估计数量， 而不是由NCRR赠款提供给子项目或子项目工作人员的直接资金。 摘要淀粉和糖占人类膳食能量摄入的60-90%。所有食物碳水化合物（CHO）在小肠中消化成单糖，然后被称为二硫代磷酸酶的膜结合型管腔酶家族吸收。研究得最好的二糖酶是乳糖酶和蔗糖酶-异麦芽糖酶。由于可识别的临床症状，先天性蔗糖酶-异麦芽糖酶缺乏症（CSID）已在临床，蛋白质组学和基因组水平上进行了研究。虽然唾液和胰腺α-淀粉酶活性在淀粉消化中的作用是众所周知的，但对粘膜α-葡糖苷酶活性的作用了解较少。α-淀粉酶仅释放支链淀粉中存在的4%的葡萄糖。其余96%的产物是具有保守长度模式的可溶性葡萄糖低聚物。这些低聚物，包括麦芽糖（G2）和G40的长度需要进一步消化。粘多糖葡糖醛酸酶从可溶性低聚物的非还原末端释放游离葡萄糖。1880年，在发现麦芽糖酶在小肠中具有活性而在胰腺中不具有活性后，首次报道了淀粉酶与葡萄糖苷酶活性的区别。在20世纪60年代，Dahlqvist发现在人类空肠中可以鉴定出4种不同的麦芽糖酶活性;两种分离出具有蔗糖酶-异麦芽糖酶（SI）活性，另外两种不具有所有其他二硫键酶活性，称为麦芽糖酶-葡糖淀粉酶（MGAM）。在20世纪80年代，Hermann等人证明粘膜麦芽糖酶活性是葡糖苷酶的一个亚组，并且虽然SI和MGAM的底物特异性相同，但MGAM的活性高100倍，SI肽的浓度高20倍。这就要求必须对两者进行研究，以了解食物淀粉的粘膜葡萄糖生产。 该方案是H-20932的通用版本，其是为遗传性淀粉消化不良的家族编写的。在本方案中，我们将研究一个全国性样本的儿童类似低的十二指肠活检麦芽糖酶和正常的蔗糖酶活动。这项研究的动力与两个年幼的兄弟姐妹有关，他们的成长失败被认为是淀粉不耐受的继发性疾病。他们寻求治疗这种目前通过饮食限制管理的疾病（见H-20932）。在年龄较大的儿童的条件已被归因于活检证实，先天性缺乏肠道刷状缘酶称为麦芽糖酶。活组织检查的葡萄糖苷酶活性为蔗糖酶40.6（nl 25）、麦芽糖酶87.1（nl 100）和帕拉金酶6.8（nl 5）。所有值均为uM/min/g蛋白质。 葡萄糖苷酶将低聚糖还原为可被人体吸收的简单葡萄糖。失败的结果是未消化的复杂碳水化合物，通过结肠和挑起气体，腹胀，易怒和腹泻。Lebenthal于1994年描述了一种类似的综合征，发现9名6-107个月的儿童患有临床淀粉不耐受。Lebenthal使用糖原作为粘膜活检葡萄糖苷酶测定的底物，并报告说缺乏活性通常与他的临床诊断一致。我们现在知道糖原底物对粘膜的MGAM活性只有约80%的特异性。在Lebenthals论文发表后的14年里，我们已经证明了四种葡萄糖苷酶参与了淀粉酶后将寡糖消化为葡萄糖的过程，并且特定的底物不能分解这些葡萄糖苷酶的活性。我们已经发现，免疫沉淀的活动可以解决个人的贡献，不同的基因淀粉消化。 假设补充口服酶治疗，含有真菌淀粉葡糖苷酶，将有利于先天性麦芽糖酶葡萄糖淀粉酶缺乏症的症状儿童，如症状改善和呼吸样本富集值增加所示（刷状缘α-极限糊精消化和产物同化的客观替代）。 I. 具体目标 1. 证明补充口服酶疗法，含有真菌淀粉葡糖苷酶，是有益的先天性麦芽糖酶葡萄糖淀粉酶缺乏症的症状儿童。 2. 证明症状改善 3. 证明呼吸样本富集值增加（刷状缘α-极限糊精消化和产物同化的客观替代物）