PURIFICATION AND CHARACTERIZATION OF A PEPTIDE FROM AMYLOID-RICH PANCREASES OF TYPE-2 DIABETIC-PATIENTS
PURIFICATION AND CHARACTERIZATION OF A PEPTIDE FROM AMYLOID-RICH PANCREASES OF TYPE-2 DIABETIC-PATIENTS
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DOI：
10.1073/pnas.84.23.8628
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发表时间：
1987-12-01
影响因子：
11.1
通讯作者：
REID, KBM
中科院分区：
文献类型：
--
作者：
COOPER, GJS;WILLIS, AC;REID, KBM
胰岛淀粉样蛋白沉积是人类2型糖尿病患者的常见特征，但由于其不溶性和组织浓度低，其单体结构尚未确定。我们描述了一种计算分子质量为3905 Da的多肽，它是三名2型糖尿病患者富含淀粉样蛋白的胰腺提取物的主要蛋白质成分。胶原酶处理后，将含有20-50%淀粉样蛋白的提取物超声溶解到70%甲酸中，然后通过凝胶过滤和反相高效液相色谱分离纯化多肽。我们称这种多肽为糖尿病相关多肽，因为在6名正常人的胰腺提取液中没有检测到这种多肽。糖尿病相关肽包含37个氨基酸，与大鼠和人降钙素基因相关肽的序列有46%的同源性，表明这些肽在进化上是相关的。在一个16个残基的片段中也发现了与胰岛素A链保守残基的序列一致性。在提取时，胰岛淀粉样蛋白是颗粒状的，像阿尔茨海默病的核心颗粒一样不可溶。它们的单体具有相似的分子质量，每个单体都有一个可能形成β-褶皱薄片的疏水性区域。胰岛淀粉样蛋白的积聚，包括糖尿病相关肽，可能会损害2型糖尿病的胰岛功能。
Deposition of amyloid in pancreatic islets is a common feature in human type 2 diabetic subjects but because of its insolubility and low tissue concentrations, the structure of its monomer has not been determined. We describe a peptide, of calculated molecular mass 3905 Da, that was a major protein component of amyloid-rich pancreatic extracts of three type 2 diabetic patients. After collagenase treatment, an extract containing 20-50% amyloid was solubilized by sonication into 70% formic acid and the peptide was purified by gel filtration followed by reverse-phase high-performance liquid chromatography. We term this peptide diabetes-associated peptide, as it was not detected in extracts of pancreas from any of six normal subjects. Diabetes-associated peptide contains 37 amino acids and is 46% identical to the sequences of rat and human calcitonin gene-related peptide, indicating that these peptides are related in evolution. Sequence identities with conserved residues of the insulin A chain were also seen in a 16-residue segment. On extraction, the islet amyloid is particulate and insoluble like the core particles of Alzheimer disease. Their monomers have similar molecular masses, each having a hydropathic region that can probably form .beta.-pleated sheets. The accumulation of amyloid, including diabetes-associated peptide, in islets may impair islet function in type 2 diabetes mellitus.