title: Characterization of glycation adducts on human serum albumin by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry.
abstract: BACKGROUND
  Non-enzymatic glycation of human serum albumin (HSA) is associated with the long-term complications of diabetes. We examined the structure and location of modifications on minimally-glycated HSA and considered their possible impact on the binding of drugs to this protein.
  
  
  METHODS
  Minimally-glycated and normal HSA (used as a control) were digested with trypsin, Glu-C or Lys-C, followed by fractionation of the resulting peptides and their analysis by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) to determine the structures and locations of glycation adducts.
  
  
  RESULTS
  Several specific lysine and arginine residues were identified as modification sites in minimally-glycated HSA. Residues K12, K51, K199, K205, K439 and K538 were found to be modified through the formation of fructosyl-lysine, while the modification of K159 and K286 involved the formation of pyrraline or N(epsilon)-carboxymethyl-lysine, respectively. Lysine K378 was found to give N(epsilon)-carboxyethyl-lysine in some forms of glycated HSA but fructosyl-lysine in other forms. Residues R160 and R472 produced a modification based on N(epsilon)-(5-hydro-4-imidazolon-2-yl)ornithine. Lysine R222 was modified to produce argpyrimidine, N(epsilon)-[5-(2,3,4-trihydroxybutyl)-5-hydro-4-imidazolon-2-yl]ornithine or tetrahydropyrimidine.
  
  
  CONCLUSIONS
  With the exception of K12, K199, K378, K439 and K525, all of the observed sites of modification for minimally-glycated HSA were new to this current study. The fact that many of these glycation-related modifications are located at or near known drug binding sites on HSA explains why some differences have been previously noted in the binding of certain drugs to normal vs glycated HSA.
authors: Department of Chemistry, University of Nebraska, Lincoln, NE 68588-0304, United States.
authors: Chunling
authors: C
authors: Wa
authors: Ronald L
authors: RL
authors: Cerny
authors: William A
authors: WA
authors: Clarke
authors: David S
authors: DS
authors: Hage
mesh_terms: D000595:Amino Acid Sequence; D050260:Carbohydrate Metabolism; D002241:Carbohydrates / Q000032:analysis* / Q000097:blood / Q000737:chemistry*; D018698:Glutamic Acid / Q000737:chemistry / Q000378:metabolism; D017127:Glycation End Products, Advanced / Q000032:analysis* / Q000097:blood; D006801:Humans; D008239:Lysine / Q000737:chemistry / Q000378:metabolism; D008958:Models, Molecular; D008969:Molecular Sequence Data; D015394:Molecular Structure; D017434:Protein Structure, Tertiary; D012709:Serum Albumin / Q000737:chemistry* / Q000378:metabolism; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*; D014357:Trypsin / Q000378:metabolism
chemical_list: D002241:Carbohydrates; D017127:Glycation End Products, Advanced; D012709:Serum Albumin; D018698:Glutamic Acid; D014357:Trypsin; D008239:Lysine
references: Biochem Pharmacol. 1992 Apr 15;43(8):1829-34
references: 1575775
references: Arch Biochem Biophys. 2003 Nov 1;419(1):1-15
references: 14568003
references: Diabetologia. 1996 Feb;39(2):149-60
references: 8635666
references: Rapid Commun Mass Spectrom. 1996;10(11):1371-8
references: 8805846
references: Electrophoresis. 1997 Mar-Apr;18(3-4):403-8
references: 9150918
references: Anal Chem. 1997 Jul 1;69(13):2457-63
references: 9212708
references: Life Sci. 1998;62(23):2141-50
references: 9627093
references: J Biol Chem. 2005 Feb 18;280(7):5724-32
references: 15557329
references: J Biol Chem. 2005 Jun 17;280(24):22582-9
references: 15837789
references: Ann N Y Acad Sci. 2005 Jun;1043:249-59
references: 16037245
references: Ann N Y Acad Sci. 2005 Jun;1043:267-75
references: 16037247
references: Proteins. 2005 Dec 1;61(4):704-21
references: 16231289
references: Anal Biochem. 2006 Feb 15;349(2):229-41
references: 16356458
references: Kidney Int. 2000 Nov;58(5):2228-34
references: 11044246
references: Mass Spectrom Rev. 2000 Sep-Oct;19(5):279-304
references: 11079246
references: Recent Prog Horm Res. 2001;56:1-21
references: 11237208
references: Electrophoresis. 2001 Aug;22(14):2844-55
references: 11565779
references: Trends Biochem Sci. 2002 Feb;27(2):107-9
references: 11852249
references: Biochem J. 2002 May 15;364(Pt 1):1-14
references: 11988070
references: Biochem J. 2002 May 15;364(Pt 1):15-24
references: 11988071
references: J Mass Spectrom. 2003 Feb;38(2):196-205
references: 12577286
references: Nucleic Acids Res. 2003 Jul 1;31(13):3316-9
references: 12824316
references: J Am Soc Mass Spectrom. 2003 Sep;14(9):992-1002
references: 12954167
references: J Biomol Tech. 2003 Sep;14(3):224-30
references: 13678153
references: Clin Pharmacokinet. 1991 Jun;20(6):477-90
references: 2044331
references: Science. 1990 Jul 20;249(4966):302-3
references: 2374930
references: Pharm Res. 1988 May;5(5):261-5
references: 3149736
references: Ther Drug Monit. 1987 Dec;9(4):389-91
references: 3122377
references: J Biol Chem. 1986 Oct 15;261(29):13542-5
references: 3759977
references: J Biol Chem. 1984 Mar 25;259(6):3812-7
references: 6706980
references: J Biol Chem. 1983 May 25;258(10):6142-6
references: 6853480
references: J Pharm Sci. 1982 Feb;71(2):235-8
references: 7062252
references: J Biol Chem. 1979 Feb 10;254(3):595-7
references: 762083
references: J Am Soc Mass Spectrom. 2004 Apr;15(4):496-509
references: 15047055
references: Biochem J. 2003 Nov 1;375(Pt 3):581-92
references: 12885296
references: Biol Pharm Bull. 1994 Nov;17(11):1505-7
references: 7703973