Tissue-specific variation in glycation of proteins in diabetes: evidence for a functional role of amadoriase enzymes.
The Amadori product fructoselysine (FL), an intermediate in the formation of many advanced glycation end products, may be deglycated by various pathways. These include spontaneous chemical degradation or enzymatic deglycation by amadoriases. This study was designed to compare changes in FL in various tissues in response to changes in glycemia, thereby testing tissue-specific deglycation. FL content in skin collagen, red cell hemoglobin, and total muscle, liver, and brain protein was analyzed by isotope dilution gas chromatography-mass spectrometry. Mean blood glucose increased over fourfold in diabetic versus control rats, whereas changes in glycation of proteins varied from fivefold in collagen to no change in the liver and brain. These results suggest significant differences among tissues in the activity of deglycating enzymes and/or protein turnover.
Brown
Sarah M
SM
Department of Chemistry and Biochemistry, University of South Carolina, Columbia SC 29208,USA. browns@mail.chem.sc.edu
Smith
Della M
DM
Alt
Nadja
N
Thorpe
Suzanne R
SR
Baynes
John W
JW
D000594:Amino Acid Oxidoreductases / Q000378:metabolism*; D000818:Animals; D001798:Blood Proteins / Q000378:metabolism; D003094:Collagen / Q000378:metabolism; D003921:Diabetes Mellitus, Experimental / Q000097:blood*; D017127:Glycation End Products, Advanced / Q000378:metabolism*; D006801:Humans; D009928:Organ Specificity; D051381:Rats; D017207:Rats, Sprague-Dawley; D012867:Skin / Q000378:metabolism
D001798:Blood Proteins; D017127:Glycation End Products, Advanced; D003094:Collagen; D000594:Amino Acid Oxidoreductases; C103012:amadoriase