Glycopeptides quantitative analysis

H. Zhang, E. C. Yi, X.-J. Li, P. Mallick, K. S. Kelly-Spratt, C. D. Masselon, D. G. Camp, R. D. Smith, C. J. Kemp, and R. Aebersold, High throughput quantitative analysis of serum proteins using glycopeptide capture and liquid chromatography mass spectrometry, Mol. Cell. Proteomics, 4 (2005) 144—155. 

L. Zhou, R. Beuerman, A. P. Chew, S. K. Koh, T. Cafaro, E. Urrets-Zavalia, J. Urrets-Zavalia, S. Li, and H. Serra, Quantitative analysis of IV-linked glycoproteins in tear fluid of climatic droplet keratopathy by glycopeptide capture and iTRAQ, J. Proteome Res., 8 (2009) 1992-2003. 

Experiments were conducted to determine the free amino groups available for reaction with dansyl chloride. Only one faint fluorescent area in the region of dansyl-lysine was observed. No dansyl-ethanolamine was observed. However, if the pol3nner was first treated with 6 N HCl to hydrolyze the amino acids, dansyl amino acids were obtained. Quantitative analysis for ethanolamine from the amino acid analyzer gave 1.3 ethanolamine residues for 2 proline residues. The low solubility of the polymer in aqueous solution may have been the primary factor leading to lack of derivatization of the intact glycopeptide. 

Lundblad, A., and Svensson, S. Quantitative Analysis of Oligosaccharides and Glycopeptides in Urine by Gas Chromatography... 

An effort was made to better quantitate this suggested preponderance of N-acetylglucosamine and/or N-acetylgalactos-amine in the carbohydrate portion of microbubble glycopeptide surfactant by performing direct HPLC analysis of the monosaccharides contained in the surfactant. This analysis began with the (carbohydrate) hydrolysis of a partially purified preparation containing approximately 30 pg of the proteinaceous microbubble... 

Although MS is most often used for qualitative analysis and structural determination, several methods have been developed for the quantitative assessment of proteins, through peptides or glycopeptides, in order to determine the extent of their over- or under-expression in cellular systems. Some proteomic methodologies use natural isotope incorporation to prepare internal standards for isotope dilution experiments. The protein concentration may then be determined by quantifying the abundances of either the peptides or glycopeptides. These methods were summarized and compared in a review produced in 2007 [119]. 

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