Identification and quantitative evaluation of the lysine-arginine crosslinks GODIC, MODIC, DODIC, and glucosepan in foods

Abstract

The presence of the various protein crosslinks GOLD 2, MOLD3, GODIC4, MODIC5, DODIC6, and glucosepan 7in foods has been established for the first time by liquid chromatography – mass spectrometry (LC‐MS) with electrospray ionization (ESI). In compounds2 and3two lysine moieties, in4–7a lysine and an arginine side chain are joined by the crosslink. Unequivocal identification of2–7 was achieved with independently synthesized reference material. The quantitative results for the investigated foodstuffs show MODIC 5to be the most important Maillard crosslink. The concentrations of 5 and GODIC 4are 5–10 fold higher than those of the corresponding imidazolium compounds3 and 2, establishing5and 4as the major food protein crosslinks derived from methylglyoxal and glyoxal, respectively. The maximum value of 151 mg MODIC 5/kg protein (equivalent to 0.42 mmol/kg protein) was found in a butter biscuit sample which also shows the highest overall Maillard crosslink content with 0.71 mmol47/kg protein. These first quantitative results suggest that compounds4–7 can be jointly responsible for protein polymerization in the course of food processing.

2-Ammonio-6-(3-oxidopyridinium-1-yl)hexanoate (OP-lysine) Is a Newly Identified Advanced Glycation End Product in Cataractous and Aged Human Lenses

“…This allowed us to produce a sufficient amount of synthetic standard to permit characterization by chemical and spectral methods. The usage of known reactions during the independent synthesis, the chemical and spectral properties of the synthetic product, and the identity of 1 H NMR, 13 C NMR, and ESI-MS spectral data obtained by us and those published by another laboratory (11) were solid evidence that the synthetic standard of OP-lysine we prepared had the structure 1, shown in Fig. 2.…”

“…Similarly to other known AGEs, the amount of OP-lysine in the biological material was not sufficient for the recording of its 13 C NMR spectrum, which is one of the key confirmations of the structure of an analyte. We were able, however, to isolate enough material for recording the 1 H NMR spectrum due to the relatively high content of this AGE in cataractous human lenses.…”

“…We found that the usage of HFBA results in a longer retention time of OP-lysine compared with trifluoroacetic acid-based eluants. Improved chromatographic separation due to HFBA was reported for other AGEs (13). This makes HFBA more appropriate for isolation of OP-lysine from complex mixtures or its chromatographic quantification.…”

Conversion of Arginine into Ornithine by Advanced Glycation in Senescent Human Collagen and Lens Crystallins

“…Similarly, MG, G, and 3DG can react with lysine and arginine to form the imidazoline cross-links MODIC, GODIC, and DOGDIC, respectively ( Fig. 1) (12)(13)(14).…”

Real Time Monitoring the Maillard Reaction Intermediates by HPLC- FTIR

“…It is also apparent that the peak at Rt 5.7 mins corresponding to asparagine increases with time at 140°C (Figure 3). In the FTIR spectra, the spectral range between 1200 and 1800 cm -1 is shown where the majority of the asparagine FTIR absorptions are found [12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30].…”