2,4-dinitrophenylhydrazine carbonyl assay in metal-catalysed protein glycoxidation.
Using an experimental in vitro glycation model, long-term incubations of bovine serum albumin with glucose (fructose) resulted in a significant increase in protein content of 2,4-dinitrophenylhydrazine (DNPH)-reactive carbonyl groups, which could be strongly inhibited by anaerobiosis and metal chelation. The pattern of yields of the protein-bound DNPH was not in accordance with that of the sugar-derived carbonyls determined as the ketoamine Amadori product. In spite of the fact that the contribution of the final advanced glycation end-products to the total DNPH-reactivity of glycation-altered protein remains unclear, the present results stress the need of oxidative steps in formation of most of the DNPH-reactive carbonyl compounds generated by glycation. The results provide evidence that, in protein glycoxidation, the DNPH assay is selective enough to discriminate between protein-bound carbonyls produced by metal-catalysed oxidations and those formed in the early glycation steps.
Stefek
M
M
Institute of Experimental Pharmacology, Slovak Academy of Sciences, Bratislava, Slovak Republic.
Trnkova
Z
Z
Krizanova
L
L
D003300:Copper / Q000494:pharmacology; D006031:Glycosylation; D010084:Oxidation-Reduction; D010659:Phenylhydrazines / Q000378:metabolism*; D011506:Proteins / Q000378:metabolism*
D010659:Phenylhydrazines; D011506:Proteins; C004787:2,4-dinitrophenylhydrazine; D003300:Copper