Protein Repair from Glycation by Glyoxals by the DJ-1 Family Maillard Deglycases.

ABSTRACT

DJ-1 and its prokaryotic homologs, Hsp31, YhbO and YajL from Escherichia coli and PfpI from Pyrococcus furiosus, repair proteins from glycation by glyoxals (R-CO-CHO), which constitute their major glycating agents. Glycation is a non-enzymatic covalent reaction discovered by Louis Camille Maillard in 1912, between reactive carbonyls (reducing sugars and glyoxals) and amino acids (cysteine, arginine and lysine), which inactivates proteins. By degrading Maillard adducts formed between carbonyls and thiols or amino groups, the DJ-1 family Maillard deglycases prevent the formation of the so-called advanced glycation end products (AGEs) that arise from Maillard adducts after dehydrations, oxidations and rearrangements. Since glycation is involved in ageing, cancer, atherosclerosis and cataracts, as well as post-diabetic, neurovegetatives and renal and autoimmune diseases, the DJ-1 deglycases are likely to play an important role in preventing these diseases. These deglycases, especially those from thermophilic organisms, may also be used to prevent the formation of dietary AGEs during food processing, sterilization and storage. They also prevent acrylamide formation in food, likely by degrading the asparagine/glyoxal Maillard adducts responsible for its formation. Since Maillard adducts are the substrates of the DJ-1 family deglycases, we propose renaming them Maillard deglycases.