Journal article


Analysis of Glycated and Ascorbylated Proteins by Gas Chromatography- Mass Spectrometry


Publication Details
Author(s): Hasenkopf K, Rönner B, Hiller H, Pischetsrieder M
Publisher: American Chemical Society
Publication year: 2002
Volume: 50
Pages range: 5697-5703
ISSN: 0021-8561

Abstract

Proteins or poly-L-lysine which were incubated in the presence of ascorbic acid, dehydroascorbic acid (ascorbylation), or various sugars (glycation) were analyzed by gas chromatography-mass spectrometry (GC-MS). To also detect more labile reaction products, the Maillard modified proteins or poly-L-lysine were enzymatically hydrolyzed and reacted with N-methyl-N-(tert-butyldimethylsilyl)-trifluoroacetamide to form the N(O)-tert-butyldimethylsilyl (tBDMS) derivatives prior to GC analysis. Under these conditions, the known Maillard products Nε-(carboxymethyl)lysine (1), oxalic acid mono-Nε-lysinylamide (2), and Nε-(carboxyethyl)lysine (3) could be simultaneously detected and quantified in glycated and ascorbylated proteins. Additionally, Nε-(1-carboxy-3-hydroxypropyl)-L-lysine (4) was identified for the first time as a Maillard product of proteins. Under the conditions applied here, 4 was found only in ascorbylated proteins or poly-L-lysine, but not in glycated proteins. Maillard-modified poly-L-lysine was further subjected to high-performance liquid chromatography (HPLC) analysis after enzymatic hydrolysis and formation of the phenyl isothiocyanate derivatized amino acids. Using this method, Nε-formyl-L-lysine (5), which cannot be distinguished from 2 by GC-MS analysis, was identified for the first time as a glycation product. Compound 5 is mainly formed from ribose, lactose, and fructose. The indicated Maillard products were quantified in β-lactoglobulin (GC-MS) or poly-L-lysine (HPLC) which were glycated or ascorbylated using different precursors.



How to cite
APA: Hasenkopf, K., Rönner, B., Hiller, H., & Pischetsrieder, M. (2002). Analysis of Glycated and Ascorbylated Proteins by Gas Chromatography- Mass Spectrometry. Journal of Agricultural and Food Chemistry, 50, 5697-5703. https://dx.doi.org/10.1021/jf020411u

MLA: Hasenkopf, Katrin, et al. "Analysis of Glycated and Ascorbylated Proteins by Gas Chromatography- Mass Spectrometry." Journal of Agricultural and Food Chemistry 50 (2002): 5697-5703.

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