title: Formation of Pentosidine Cross-Linking in Myoglobin by Glyoxal: Detection of Fluorescent Advanced Glycation End Product.
abstract: Glyoxal, a reactive α-oxoaldehyde, increases in diabetic condition and reacts with proteins to form advanced glycation end products (AGEs) following Maillard-like reaction. Considering the significance of protein modification by glyoxal-derived AGEs, we investigated the in vitro effect of glyoxal (200 μM) on the monomeric heme protein myoglobin (Mb) (100 μM) after incubation for one week at 25 °C. Glyoxal-treated Mb exhibited increased absorbance around the Soret region, decreased α-helicity and thermal stability compared to control Mb. Intrinsic fluorescence spectrum of the treated Mb showed an additional signal in the 400-500 nm region on excitation at 280 nm that was absent in control Mb. When excited at 335 nm, the glyoxal-treated sample gave a strong fluorescence indicating AGE formation. Mass spectrometric studies revealed formation of glyoxal-derived fluorescent AGE adduct pentosidine between Lys-145 and Arg-139 residues of Mb. Other than pentosidine, additional AGE adducts, namely, carboxymethyllysine at Lys-133, hydroimidazolone at Arg-31 and pyrrolidone-carboxymethyllysine at Lys-145 were also detected. Lys-145 was thus found to contain two different types of AGE adducts, indicating the heterogeneous nature of in vitro glycation reaction. AGE-induced protein modifications might be associated with complications in disease conditions.
authors.affiliation: Indian Institute of Science Bangalore, C V Raman Ave, Devasandra Layout, Bengaluru, 560012, Karnataka, India. dipta.saura@gmail.com.
authors.forename: Sauradipta
authors.initials: S
authors.lastname: Banerjee
mesh_terms: D001120:Arginine / Q000031:analogs & derivatives* / Q000737:chemistry; D003432:Cross-Linking Reagents / Q000737:chemistry*; D017127:Glycation End Products, Advanced / Q000032:analysis*; D006031:Glycosylation; D006037:Glyoxal / Q000737:chemistry*; D006801:Humans; D008239:Lysine / Q000031:analogs & derivatives* / Q000737:chemistry; D009211:Myoglobin / Q000737:chemistry*
chemical_list: D003432:Cross-Linking Reagents; D017127:Glycation End Products, Advanced; D009211:Myoglobin; D006037:Glyoxal; D001120:Arginine; C062187:pentosidine; D008239:Lysine
keywords: Advanced glycation end products; Carboxymethyllysine; Glyoxal; Hydroimidazolone; Myoglobin; Pentosidine