Tissue-specific variation in glycation of proteins in diabetes: evidence for a functional role of amadoriase enzymes

Ann N Y Acad Sci. 2005 Jun;1043:817-23. doi: 10.1196/annals.1333.094.


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.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.
  • Review

MeSH terms

  • Amino Acid Oxidoreductases / metabolism*
  • Animals
  • Blood Proteins / metabolism
  • Collagen / metabolism
  • Diabetes Mellitus, Experimental / blood*
  • Glycation End Products, Advanced / metabolism*
  • Humans
  • Organ Specificity
  • Rats
  • Rats, Sprague-Dawley
  • Skin / metabolism


  • Blood Proteins
  • Glycation End Products, Advanced
  • Collagen
  • Amino Acid Oxidoreductases
  • amadoriase