The reaction of malondialdehyde with lens proteins and the protective effect of aspirin.
Malondialdehyde, a product of lipid peroxidation and a by-product of thromboxane synthesis increases in human cataract. Malondialdehyde bound to soluble lens proteins over 4 h of incubation. Pre-incubation of lens proteins with aspirin offered protection against reaction with MDA. Gel chromatography was used to monitor aggregation of the modified protein. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed that the reaction with malondialdehyde led to non-disulphide covalent cross-linking of gamma-crystallin, which was decreased by incubation with aspirin. Malondialdehyde has two carbonyl groups which could react with primary amino groups, forming Schiff-base conjugates and covalently cross-link proteins. The modification and cross-linking could initiate the cataractogenic process.
Nuffield Laboratory of Ophthalmology, University of Oxford, UK.
M L
ML
Riley
J J
JJ
Harding
D000082:Acetaminophen / Q000494:pharmacology; D000818:Animals; D001241:Aspirin / Q000494:pharmacology*; D002417:Cattle; D003459:Crystallins / Q000737:chemistry*; D007052:Ibuprofen / Q000494:pharmacology; D008315:Malondialdehyde / Q000032:analysis / Q000737:chemistry*
D003459:Crystallins; D000082:Acetaminophen; D008315:Malondialdehyde; D001241:Aspirin; D007052:Ibuprofen