Peptides are building blocks of heat-induced fibrillar protein aggregates of β-lactoglobulin formed at pH 2
Peptides are building blocks of heat-induced fibrillar protein aggregates of β-lactoglobulin formed at pH 2
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DOI：
10.1021/bm7014224
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发表时间：
2008-05-01
影响因子：
6.2
通讯作者：
van der Linden, Erik
中科院分区：
文献类型：
--
作者：
Akkermans, Cynthia;Venema, Paul;van der Linden, Erik
在pH 2下加热（在85℃下加热20小时）后形成的β -乳球蛋白原纤维中存在的蛋白质物质在本研究中得到了鉴定。将原纤维从未聚集的材料中分离出来，用8 M氯胍和0.1 M 1,4-二硫苏糖醇（pH 8）解离原纤维。采用硫黄素T荧光、高效粒径排除色谱、反相高效液相色谱和质谱（MALDI-TOF）对不同组分进行表征。-乳球蛋白被水解成分子质量在2000 ~ 8000 Da之间的肽，原纤维由这些肽的一部分组成，而不是完整的-乳球蛋白。大多数肽（包括聚集的和非聚集的）是在天冬氨酸残基之前或之后肽键断裂的结果。原纤维中存在某些肽片段的解释是疏水性、低电荷、电荷分布和形成p片的能力。
The proteinaceous material present in beta-lactoglobulin fibrils formed after heating (20 h at 85 degrees C) at pH 2 was identified during this study. Fibrils were separated from the nonaggregated material, and the fibrils were dissociated using 8 M guanidine chloride and 0.1 M 1,4-dithiothreitol (pH 8). Characterization of the different fractions was performed using thioflavin T fluorescence, high-performance size-exclusion chromatography, reversed-phase HPLC, and mass spectrometry (MALDI-TOF). beta-Lactoglobulin was found to be hydrolyzed into peptides with molecular masses between 2000 and 8000 Da, and the fibrils were composed of a part of these peptides and not intact beta-lactoglobulin. The majority of the peptides (both aggregated and nonaggregated) were a result from cleavage of the peptide bonds before or after aspartic acid residues. Explanations for the presence of certain peptide fragments in the fibrils are the hydrophobicity, low charge, charge distribution, and capacity to form P-sheets.