Mass spectrometric detection method of A1/A2 beta-casein

Abstract

The invention discloses a mass spectrometric detection method of A1 / A2 beta-casein. The mass spectrometric detection method comprises the following steps that a) the amino acid sequence of A2 beta-casein is obtained; b) 67-site amino acid proline of A2 beta-casein is modified to be histidine, and the amino acid sequence of A1 beta-casein is obtained; c) a to-be-tested protein is cut to be a polypeptide segmented mixture with the low molecular mass by using a specific enzymolysis method, the molecular mass and segment information of polypeptides in the mixture are detected by utilizing an electrostatic field orbitrap high resolution mass spectrum full scanning mode and compared with the previous amino acid sequence, and whether the feature peptide fragment of A1 or A2 beta-casein exists ornot is determined qualitatively; and d) the fragment determined to be the feature peptide fragment of A1 or A2 beta-casein is selected to synthesize the isotope internal standard peptide fragment, andquantitative analysis is conducted by utilizing tandem quadrupole mass spectrometry to build a multiple reaction monitoring method. The mass spectrometric detection method can achieve qualitative identification and quantitative research of A1 and A2 beta-casein simultaneously, is high in sensitivity, precision and anti-interference capability, and can be widely applied to confirmation and detection of A2 milk products.

Description

technical field [0001] The invention relates to a protein mass spectrometry detection method, in particular to a mass spectrometry detection method for A1 / A2β-casein. Background technique [0002] Casein is the most abundant protein in milk and a source of important bioactive peptides. β-casein accounts for about 40% of the casein content in milk, and is an important source of amino acids. At the same time, it transmits important minerals (such as calcium and phosphorus) in the body to promote its digestion and absorption. β-casein is encoded by the CSN2 gene on chromosome 6, which is a highly polymorphic gene. To date, 15 different β-casein gene variants have been identified, of which A1 and A2 β-casein Yes, bovine beta-casein is the two most common forms. A2 β-casein is recognized as the natural prototype of modern cow β-casein. Initially, all domesticated cattle contained A2β-casein, and about 5,000 years ago, the crossbreeding of European cows led to the mutation of m...

AI Technical Summary

Problems solved by technology

Mass spectrometry coupled with electrospray ionization (ESI) is by far the most reliable peptide detection technology, but the current mass spectrometry-based detection technology is mainly focused on the detection of the enzymatic hydrolysis product BCM-7 of A1, and cannot simultaneously characterize and detect A2β-casein. Quantitative detection

Due to the lack of effective testing methods, and the relevant testing standards have not been issued domestically and internationally, therefore, the interests of consumers cannot be guaranteed

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