Identification of casein phosphopeptides in β-casein and commercial hydrolysed casein by mass spectrometry
Casein phosphopeptides (CPPs) in commercial hydrolysed casein (CE90CPP) and in -CN (-CN) after simulated gastrointestinal digestion (gastric stage pepsin, pH 2, 37ºC 2h) and intestinal stage (pancreatic-bile extract, pH 5.2, 37ºC 2h) were sequenced by on-line reversed-phase high performance liquid c...
| Autores: | , , , , , |
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| Tipo de recurso: | artículo |
| Estado: | Versión publicada |
| Fecha de publicación: | 2006 |
| País: | España |
| Institución: | Consejo Superior de Investigaciones Científicas (CSIC) |
| Repositorio: | DIGITAL.CSIC. Repositorio Institucional del CSIC |
| OAI Identifier: | oai:digital.csic.es:10261/417532 |
| Acceso en línea: | http://hdl.handle.net/10261/417532 |
| Access Level: | acceso abierto |
| Palabra clave: | Casein phosphopeptides Mineral bioavailability Simulated gastrointestinal digestion |
| Sumario: | Casein phosphopeptides (CPPs) in commercial hydrolysed casein (CE90CPP) and in -CN (-CN) after simulated gastrointestinal digestion (gastric stage pepsin, pH 2, 37ºC 2h) and intestinal stage (pancreatic-bile extract, pH 5.2, 37ºC 2h) were sequenced by on-line reversed-phase high performance liquid chromatography coupled to electrospray ionisation tandem mass spectrometry (RP-HPLC-ESIMS/MS). In -CN digest five peptides that contained four to five phosphate groups and the cluster sequence SpSpSpEE (residues 17–21) were identified. All CPPs with one exception -CN(1-24)4P, had the protein fragment -CN(1-25)4P, which is one of the main CPPs produced in vivo digestion of casein and the results of in vitro studies showed that this fragment enhanced calcium, iron and zinc absorption. In commercial hydrolysed casein CE90CPP 13 peptides were identified, only one of them, s2-CN (113)3P, contained the cluster sequence SpSpSpEE but all the peptides have one or two phosphoserine residues with mineral binding capacity. These CPPs were shorter (527-2061 Da vs 2966-6512 Da) and less phosphorylated (1-3 P vs 4-5 P) than those released after simulated gastrointestinal digestion of -CN. In both samples, the potential mineral chelating properties of these peptides in relation to their amino acid sequences and the presence of the phosphorylated cluster are discussed. |
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