DYN 12, a small molecule inhibitor of the enzyme amadorase, lowers plasma 3-deoxyglucosone levels in diabetic rats

Advancing the development of glycated protein biosensing technology: next-generation sensing molecules

Research advances in biochemical molecules have led to the development of convenient and reproducible biosensing molecules for glycated proteins, such as those based on the enzymes fructosyl amino acid oxidase (FAOX) or fructosyl peptide oxidase (FPOX). Recently, more attractive biosensing molecules with potential applications in next-generation biosensing of glycated proteins have been aggressively reported. We review 2 such molecules, fructosamine 6-kinase (FN6K) and fructosyl amino acid-binding protein, as well as their recent applications in the development of glycated protein biosensing systems. Research on FN6K and fructosyl amino acid-binding protein has been opening up new possibilities for the development of highly sensitive and proteolytic-digestion-free biosensing systems for glycated proteins.

Genetic control of amadori product degradation in Bacillus subtilis via regulation of frlBONMD expression by FrlR

Bacillus subtilis is capable of degrading fructosamines. The phosphorylation and the cleavage of the resulting fructosamine 6-phosphates is catalyzed by the frlD and frlB gene products, respectively. This study addresses the physiological importance of the frlBONMD genes (formerly yurPONML), revealing the necessity of their expression for growth on fructosamines and focusing on the complex regulation of the corresponding transcription unit. In addition to the known regulation by the global transcriptional regulator CodY, the frl genes are repressed by the convergently transcribed FrlR (formerly YurK). The latter causes repression during growth on substrates other than fructosamines. Additionally, we identified in the first intergenic region of the operon an FrlR binding site which is centrally located within a 38-bp perfect palindromic sequence. There is genetic evidence that this sequence, in combination with FrlR, contributes to the remarkable decrease in the transcription downstream of the first gene of the frl operon.

Enzymatic deglycation of proteins

Reducing sugars such as glucose react with amino groups in proteins to form the Amadori product, which can undergo a wide range of chemical modifications and form cross-links in tissue proteins. There is growing evidence to suggest that accumulation of glycation products is associated with aging and disease progression, as in diabetes. Thus, the design and discovery of inhibitors for the glycation cascade would potentially offer a promising therapeutic approach for the prevention of glycation related diseases, especially diabetes. Two types of enzymes, fructosyl lysine oxidase and fructose lysine 3-phosphokinase, catalyze the deglycation reaction and generate free amine groups. This paper reviews the biochemical properties of these "amadoriase" enzymes, such as structural-function relationship, kinetic mechanism, and substrate specificity, as well as their biological roles and applications in the protein deglycation.