title: Glycated lysine increases in serum samples stored at -20 degrees C.
abstract: The glycated lysine in serum protein was determined by HPLC measurement of furosine in hydrolyzed serum, with synthetic N alpha-Boc-N epsilon-(1-deoxy-D-fructosyl)-L-lysine as the standard. The glycated lysine value increased with time of storage when the serum was kept at -20 degrees C, possibly because of an ongoing reaction between glucose and the epsilon-amino groups of lysine in the frozen serum. The problem was eliminated by using storage at -70 degrees C or by acidifying the serum before storing it at -20 degrees C.
mesh_terms: D001798:Blood Proteins / Q000032:analysis*; D002851:Chromatography, High Pressure Liquid; D002951:Citrates; D019343:Citric Acid; D003920:Diabetes Mellitus / Q000097:blood; D005615:Freezing; D006023:Glycoproteins; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008239:Lysine / Q000031:analogs & derivatives* / Q000097:blood; D013997:Time Factors; D000093422:Glycated Serum Proteins; D017127:Glycation End Products, Advanced
chemical_list: D001798:Blood Proteins; D002951:Citrates; D019343:Citric Acid; D006023:Glycoproteins; D008239:Lysine; D000093422:Glycated Serum Proteins; C028040:glycated lysine; D017127:Glycation End Products, Advanced; C018948:furosine