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标题：A chromatographic procedure for semi-quantitative evaluation of caseinphosphopeptides in cheese
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作者：Coralie Dupas ; Isabelle Adt ; Amandine Cottaz 等
期刊名称：Dairy Science & Technology
印刷版ISSN：1958-5586
电子版ISSN：1958-5594
出版年度：2009
卷号：89
期号：6
页码：519-529
DOI：10.1051/dst/2009027
语种：English
出版社：EDP Sciences
摘要：Caseinphosphopeptides (CPPs) are phosphorylated fragments of caseins, which are found in dairy products. One of their unique features is their ability to bind calcium. There are several published methods to extract CPPs from cheese, but none allows their quantitative evaluation. A chromatographic procedure allowing a semi-quantitative evaluation of cheese CPPs was adapted from a previously published method and tested on Beaufort cheese. Water-soluble peptides were extracted from cheese and purified using cation-exchange chromatography followed by immobilised metal-ion affinity chromatography (IMAC). CPPs were identified using mass spectrometry (LC-ESI-MS/MS). Fifty-five peptides, including 48 CPPs carrying one to three phosphorylations, were identified in Beaufort cheese. It can thus be considered that the selectivity of the chromatographic procedure proposed is sufficient for a semi-quantification of CPPs with a molecular mass ranging from 600 to 10 000 g$\cdot $mol$^{-1}$ in cheese. As IMAC fractions contain molecules with a molecular mass $<$ 600 g$\cdot $mol$^{-1}$ (such as phosphoserine), a gel filtration step was performed in order to remove these compounds. The semi-quantification based on an estimation of the extinction molar coefficient of CPPs at 215 nm allowed to estimate that the CPPs content of the fresh Beaufort cheese sample analysed was around 1.9 g$\cdot $100 g$^{-1}$.
关键词：caseinphosphopeptide;cheese;liquid chromatography;mass spectrometry