title: Characterization of advanced glycation end products for biochemical studies: side chain modifications and fluorescence characteristics.
abstract: Advanced glycation end products (AGEs) are known to be involved in the pathogenesis of several diseases and therefore effects of AGEs on cells are the objective of numerous investigations. Since AGEs used in biochemical studies are usually not chemically characterized, comparison of data is difficult if not impossible. To find a suitable characterization protocol, human serum albumin was reacted with different concentrations of glucose, methyl glyoxal, and glyoxylic acid. The obtained AGEs were characterized with respect to the extent of side chain modifications (lysine and arginine), the carboxymethyl lysine and carbonyl content, and the fibrillar state. Additionally, their fluorescence and absorbance characteristics were extensively studied. Although we found significant differences in the degree of modification and in AGE-specific fluorescence when using different modifiers, the results provide important information and allow comparing AGEs derived from different modifier concentrations. The results also suggest strong conformational changes within the modified proteins. In the present paper we propose a set of parameters that is sufficient to partially characterize AGEs used for biochemical studies.
authors.affiliation: Interdisciplinary Centre of Clinical Research Leipzig, Inselstrasse 22, 04103 Leipzig, Germany. annett_eckert@web.de
authors.forename: Annett
authors.initials: A
authors.lastname: Schmitt
authors.forename: Johannes
authors.initials: J
authors.lastname: Schmitt
authors.forename: Gerald
authors.initials: G
authors.lastname: Münch
authors.forename: Jovana
authors.initials: J
authors.lastname: Gasic-Milencovic
mesh_terms: D000596:Amino Acids / Q000737:chemistry*; D005450:Fluorescamine / Q000737:chemistry; D005947:Glucose / Q000737:chemistry; D017127:Glycation End Products, Advanced / Q000737:chemistry*; D006031:Glycosylation; D006038:Glyoxylates / Q000737:chemistry; D006801:Humans; D011487:Protein Conformation; D011765:Pyruvaldehyde / Q000737:chemistry; D012709:Serum Albumin / Q000737:chemistry; D013050:Spectrometry, Fluorescence
chemical_list: D000596:Amino Acids; D017127:Glycation End Products, Advanced; D006038:Glyoxylates; D012709:Serum Albumin; D005450:Fluorescamine; D011765:Pyruvaldehyde; D005947:Glucose; C031150:glyoxylic acid