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Published on: September 9, 2013
Quantification of αS1-casein in breast milk using a targeted mass spectrometry-based approach
Irina Altendorfer1, Simone König2, Achim Braukmann3
1Heinrich-Heine-Universität Düsseldorf, Department of Rheumatology, Moorenstr. 5, 40225 Düsseldorf, Germany; Westfälische Wilhelms-Universität Münster, PharmaCampus, Institute of Pharmaceutical and Medicinal Chemistry, Corrensstr. 48, 48149 Münster, Germany.
Insights
This study directly measured alphaS1-casein (CSN1S1) in human milk using mass spectrometry. We quantified CSN1S1 levels in early postpartum breast milk, providing a new direct measurement method.
Area of Science:
- Biochemistry
- Immunology
- Nutritional Science
Background:
- Caseins are milk proteins with nutritional and immunological significance.
- AlphaS1-casein (CSN1S1) is a potential autoantigen.
- Previous CSN1S1 quantification in human milk relied on indirect methods.
Purpose of the Study:
- To directly quantify alphaS1-casein (CSN1S1) content in human breast milk.
- To establish a mass spectrometry-based method for CSN1S1 measurement.
- To analyze CSN1S1 levels in early postpartum milk samples.
Main Methods:
- Utilized liquid chromatography-tandem mass spectrometry (LC-MS/MS).
- Quantification based on tryptic CSN1S1 peptides with optimal response.
- Developed targeted experiments for sensitive detection at the fmol level.
Main Results:
- Successfully developed a direct CSN1S1 quantification method.
- Analyzed 20 breast milk samples from the first week postpartum.
- Measured CSN1S1 concentrations ranging from 3 to 540 μg/ml.
Conclusions:
- Direct measurement of CSN1S1 in human milk is feasible using LC-MS/MS.
- This method offers specific and sensitive quantification.
- The study provides baseline data for CSN1S1 levels in early lactation.
Abstract:
The caseins comprise a milk protein fraction of high nutritional value and, as more recently discovered, of immunologic relevance. In particular, αS1-casein (CSN1S1) is of interest being a potential autoantigen. So far, the concentration of caseins in human milk was primarily determined by indirect methods. The aim of this study was to directly measure the CSN1S1 content in breast milk using mass spectrometry (MS). The quantification was based on tryptic CSN1S1 peptides with the best response in liquid chromatography (LC)-MS/MS analysis. Targeted experiments allowed both specific and sensitive detection at the low fmol level. For this pilot study, twenty breast milk samples of the first week post-partum were analyzed and contained between 3 and 540μg/ml CSN1S1. Limitations of CSN1S1 quantification are discussed.
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