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Ultra performance liquid chromatography-mass spectrometric determination of the site specificity of modification of β-casein by glucose and methylglyoxal

Lima, Maria; Moloney, Catherine; Ames, Jennifer

Authors

Maria Lima

Catherine Moloney



Abstract

Modification of protein by carbonyl compounds under in vitro physiological conditions is site-directed. There are few reports of the site specificity of glycation of proteins using heating conditions of relevance to food processing. The aim of this study was to determine the site specificity of modification of β-casein (βCN) by glucose and methylglyoxal (MGO). βCN (1.33 M, 3.2%) was heated with either glucose (1.345 M, 4.6%) or MGO (1 mM) at 95°C for up to 4 h. Tryptic digests were prepared and analysed by ultra performance liquid chromatography electrospray ionisation mass spectrometry (UPLC-ES/MS). The sites of formation of the Amadori product, N ε -(fructosyl)lysine (FL), and the advanced glycation end-products, N ε -(carboxymethyl)lysine (CML), MGO-derived dihydroxyimidazolidine (MG-DH) and MGO-derived hydroimidazolone (MG-HI), were located. FL and CML were detected at K107 and K176 residues in βCN/glucose incubations. Indigenous N ε -(lactulosyl)lysine was detected at K107 only. MG-DH and MG-HI were detected at R202 and possibly R183 residues in both βCN/glucose and βCN/MGO incubations. Glycation of βCN by glucose and MGO resulted in similar site specificity for MG-DH and MG-HI formation. © 2008 Springer-Verlag.

Citation

Ames, J. M., Lima, M., Moloney, C., & Ames, J. (2009). Ultra performance liquid chromatography-mass spectrometric determination of the site specificity of modification of β-casein by glucose and methylglyoxal. Amino Acids, 36(3), 475-481. https://doi.org/10.1007/s00726-008-0105-y

Journal Article Type Article
Publication Date Mar 1, 2009
Journal Amino Acids
Print ISSN 0939-4451
Publisher Springer (part of Springer Nature)
Peer Reviewed Not Peer Reviewed
Volume 36
Issue 3
Pages 475-481
DOI https://doi.org/10.1007/s00726-008-0105-y
Keywords advanced glycation end-products, Ne-(fructosyl)lysine, Ne-(carboxymethyl)lysine, MGO-derived dihydroxyimidazolidine, MGO-derived hydroimidazolone
Public URL https://uwe-repository.worktribe.com/output/1003927
Publisher URL http://dx.doi.org/10.1007/s00726-008-0105-y