Premium
Comparison between modifications of lens proteins resulted from glycation with methylglyoxal, glyoxal, ascorbic acid, and fructose
Author(s) -
Argirova Mariana,
Breipohl Winrich
Publication year - 2002
Publication title -
journal of biochemical and molecular toxicology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.526
H-Index - 58
eISSN - 1099-0461
pISSN - 1095-6670
DOI - 10.1002/jbt.10031
Subject(s) - methylglyoxal , glycation , chemistry , ascorbic acid , glyoxal , biochemistry , tryptophan , acrolein , crystallin , dehydroascorbic acid , amino acid , organic chemistry , enzyme , receptor , food science , catalysis
Cataract is generally associated with the breakdown of the lens microarchitecture. Age‐dependent chemical modifications and cross‐linking of proteins are the major pathways for development of lens opacity. The specific alterations in lens proteins caused by glycation with four carbonyl metabolites, fructose, methylglyoxal, glyoxal, and ascorbic acid, were investigated. Decrease in intensity of tryptophan related fluorescence and level of reduced protein sulfhydryl groups, parameters that are indicative for changes in protein conformation, were observed after reaction with all studied carbonyl compounds. Protein carbonyl content, an index for oxidative damage to proteins, was strongly enhanced in methylglyoxal‐treated proteins. Cross‐linking of glycated proteins was confirmed by polyacrylamide electrophoresis. α‐Oxoaldehydes were the most reactive in protein aggregation. They also formed specific chromophores absorbing UV light above 300 nm. Significant loss in lactate dehydrogenase activity resulted from incubation with methylglyoxal, followed by glyoxal and ascorbic acid. The results obtained showed that alterations in lens proteins do not follow the specific reactivity of studied carbonyl compounds. Despite the similarity in chemical structures of α‐oxoaldehydes and ascorbic acid degradation products, they cause specific alterations in lens protein structure with different biological consequences. © 2002 Wiley Periodicals, Inc. J Biochem Mol Toxicol 16:140–145, 2002. DOI 10.1002/jbt.10031