title: Investigation of non-enzymatic glycosylation of human serum albumin using ion trap-time of flight mass spectrometry.
abstract: Non-enzymatic glycosylation or glycation involves covalent attachment of reducing sugar residues to proteins without enzyme participation. Glycation of glucose to human serum albumin in vivo is related to diabetes and many other diseases. We present an approach using liquid chromatography coupled to an electrospray ionization source of a hybrid ion trap-time of flight (IT-TOF-MS/MS) tandem mass spectrometer to identify the glycation sites on serum albumin from both a healthy person and a diabetic patient. The MetID software, which is commonly used for screening metabolites, is adapted for  peptide fingerprinting based on both m/z values and isotopic distribution profiles. A total  of 21 glycation sites from the healthy person and 16 glycation sites from the diabetic patient were identified successfully. We also demonstrate the use of matrix assisted laser desorption ionization-time of flight mass spectrometry to estimate the incorporation ratio of glucose to albumin during glycation. Results from this study show that the glycation  in healthy person is more complicated than previously thought. Further analysis of incorporation ratio distribution may be necessary to accurately reflect the change of serum albumin glycation in diabetic patients.
authors: National Glycoengineering Research Center, Shandong University, Jinan, Shandong 250100, China. bxsy8011@sina.com
authors: Xue
authors: X
authors: Bai
authors: Zhangjie
authors: Z
authors: Wang
authors: Chengcai
authors: C
authors: Huang
authors: Zhe
authors: Z
authors: Wang
authors: Lianli
authors: L
authors: Chi
mesh_terms: D000595:Amino Acid Sequence; D002846:Chromatography, Affinity; D003924:Diabetes Mellitus, Type 2 / Q000097:blood; D017127:Glycation End Products, Advanced; D006031:Glycosylation; D006801:Humans; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000737:chemistry; D010449:Peptide Mapping; D059748:Proteolysis; D012709:Serum Albumin / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D014357:Trypsin / Q000737:chemistry; D000093423:Glycated Serum Albumin
chemical_list: D017127:Glycation End Products, Advanced; D010446:Peptide Fragments; D012709:Serum Albumin; D014357:Trypsin; D000093423:Glycated Serum Albumin