Glycation of a lysine-containing tetrapeptide by D-glucose and D-fructose--influence of different reaction conditions on the formation of Amadori/Heyns products.
The site specificity, extent, and nature of modification of the tetrapeptide, Leu-Ser-Lys-Leu (1), incubated with d-glucose or d-fructose in methanol, or in phosphate buffer of pH 5.7, 7.4, and 8.0 were investigated. The generated mono- and di-glycated Amadori (1-deoxy-d-fructosyl derivatives) and Heyns rearrangement products (N-alkylated glucosamine/mannosamine derivatives) were isolated and characterized by NMR and mass spectrometry. The results identified the epsilon-amino group of the Lys residue as the preferential glycation site in tetrapeptide 1. Under all conditions investigated, glucose afforded higher yields of glycation products than fructose. In the reactions carried out in buffer, glycation at pH 7.4 and 8.0 was much faster than at pH 5.7.
Jakas
Andreja
A
Division of Organic Chemistry and Biochemistry, Rudjer Bosković Institute, PO Box 180, Bijenicka 54, HR-10002 Zagreb, Croatia. jakas@irb.hr
Katić
Anja
A
Bionda
Nina
N
Horvat
Stefica
S
D002240:Carbohydrate Sequence; D002851:Chromatography, High Pressure Liquid; D005632:Fructose / Q000737:chemistry / Q000378:metabolism*; D005947:Glucose / Q000737:chemistry / Q000378:metabolism*; D017127:Glycation End Products, Advanced / Q000138:chemical synthesis* / Q000737:chemistry; D006031:Glycosylation; D006863:Hydrogen-Ion Concentration; D008239:Lysine / Q000378:metabolism*; D009682:Magnetic Resonance Spectroscopy; D010455:Peptides / Q000737:chemistry / Q000378:metabolism*; D013997:Time Factors
D017127:Glycation End Products, Advanced; D010455:Peptides; D005632:Fructose; D005947:Glucose; D008239:Lysine