A comprehensive survey of the acid-stable fluorescent cross-links formed by ribose with basic amino acids, and partial characterization of a novel Maillard cross-link.
Cross-linking of proteins by sugars is thought to be involved in the pathogenesis of a variety of disorders associated with diabetes and aging; however, the molecular mechanisms involved in this process are not well understood. A new, general method for cross-link analysis, using precolumn derivatization with the reagent diphenylborinic acid (DPBA), was applied to the problem of detection and characterization of Maillard (sugar-derived) cross-links. DPBA analysis of reaction mixtures containing ribose, lysine, and arginine showed the presence of the Maillard cross-link pentosidine, along with a novel cross-link which was also found in acid hydrolyzates of ribose-treated proteins. Evidence is presented that this cross-link and pentosidine are the major acid-stable fluorescent cross-links formed by ribose with basic amino acids. Since it was determined that the new cross-link is derived from two lysine residues and at least one pentose per molecule, it was named penK2. PenK2 was found to be identical, by three different methods of chromatographic analysis, to the Maillard product "LM1', which was isolated from cataractous lens by Nagaraj and Monnier, but not yet structurally characterized (Biochim. Biophys. Acta 1116, (1992) 34-42).
Graham
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Department of Orthopedic Research, Children's Hospital Medical Center, Boston, MA, USA.
D000596:Amino Acids / Q000737:chemistry*; D001120:Arginine / Q000031:analogs & derivatives / Q000737:chemistry; D001896:Boron Compounds; D003432:Cross-Linking Reagents; D006639:Histidine / Q000737:chemistry; D006851:Hydrochloric Acid; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D008239:Lysine / Q000031:analogs & derivatives / Q000737:chemistry; D015416:Maillard Reaction; D009113:Muramidase / Q000737:chemistry; D012266:Ribose / Q000737:chemistry*; D012710:Serum Albumin, Bovine / Q000737:chemistry; D013050:Spectrometry, Fluorescence
D000596:Amino Acids; D001896:Boron Compounds; D003432:Cross-Linking Reagents; C044960:diphenylborinic acid; D012710:Serum Albumin, Bovine; D006639:Histidine; D012266:Ribose; D001120:Arginine; C062187:pentosidine; D009113:Muramidase; D008239:Lysine; D006851:Hydrochloric Acid