Effect of carbohydrate structure and concentration on the non-enzymatic glycosylation and subsequent cross-linking of collagen.
It has been previously demonstrated that non-enzymatic glycosylation and subsequent cross-linking of proteins can occur at high or greater than physiological concentrations of glucose. Soluble collagen was incubated in the presence of increasing glucose concentrations. The amount of cross-linked collagen was determined by polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate. Our findings reveal that cross-linking due to non-enzymatic glycosylation occurs at or near physiological concentrations of glucose (3.11-4.22 mM). In addition, this glucose induced cross-linking is a time dependent reaction. When collagen was incubated with a variety of different carbohydrates it was found that ketoses are more active cross-linking agents than aldoses. The addition of a reactive group (such as an amine) alpha to the aldehyde group on the carbohydrate increases the cross-linking activity of glucose 2.8 fold. Blockage of the reactive group alpha to the aldehyde (such as N-acetyl glucosamine or 2-deoxy-D-glucose) totally abolishes glycosylation activity. Both 5-C and 7-C carbohydrates are more active than 6-C carbohydrates. Thus, although glucose may be the most abundant carbohydrate capable of non-enzymatic glycosylation and subsequent cross-linking, it is not the most chemically reactive. However, the significance of these findings to the pathogenesis of diabetes needs to be defined.
Counts
D F
DF
Lilly Research Laboratories, Eli Lilly and Co., Lilly Corporate Center, Indianapolis, IN 46285.
Shaw
W N
WN
D000818:Animals; D001786:Blood Glucose / Q000378:metabolism; D003094:Collagen / Q000031:analogs & derivatives* / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism; D003432:Cross-Linking Reagents; D004591:Electrophoresis, Polyacrylamide Gel; D006031:Glycosylation; D008297:Male; D009005:Monosaccharides; D051381:Rats; D013710:Tendons
D001786:Blood Glucose; D003432:Cross-Linking Reagents; D009005:Monosaccharides; C022814:glycosylated collagen; D003094:Collagen