Место издания:Hungarian Academy of Sciences, Budapest Budapest
Первая страница:47
Последняя страница:47
Аннотация:Glycation of proteins is significantly accelerated with the increase in the blood glucose level in patients with diabetes. However, there are little data on glycation of the glycolytic enzyme glyceraldehyde-3-phosphate dehydrogenase (GAPDH). We investigated the effect of glycation of GAPDH on the catalytic properties of the enzyme and on its stability. The enzyme was glycated in the presence of 20 mM glucose or 1 mM glyceraldehyde-3-phosphate (G-3-P). The enzymatic activity of GAPDH decreased by 90% and 50% after 24 h of incubation in the presence of G-3-P and glucose, respectively. The addition of β-mercaptoethanol or glutathione partially defended the enzyme from inactivation. The glycation decreased thermal stability of GAPDH and increased its propensity to aggregate. Thus, it was demonstrated that the substrate of the reaction catalyzed by GAPDH, glyceraldehyde-3-phosphate, inactivates the enzyme and promotes its denaturation and aggregation. We suppose that glycation of GAPDH may be an important regulatory mechanism controlling the rate of ATP-producing stages of glycolysis. Besides, considering the involvement of GAPDH in the induction and development of neurodegenerative diseases, the modification of this protein by sugars and aldehydes may affect its ability to produce amyloid structures with different amyloidogenic proteins, such as beta-amyloid peptide and alpha-synuclein.