Modification Of Methionine Residues Research Articles

The Study on Antioxidation and Mechanism of 2 - Bromo - 4'- Nitroacetophenone

The 2-Bromo-4'-nitroacetophenone is an important compound which is widely used in the modification of methionine residues in alpha-chymotrypsin, organic synthesis materials and pharmaceutical intermediates. Our laboratory recently found that the 2-bromo-4'-nitroacetophenone can extend the lifespan of the C. elegans. Therefore, we want to know whether this compound has the anti-oxidative ability.In this paper, we used three different concentrations of 2-bromo-4'-nitroacetophenone to feed normal C. elegans and the mutants (daf-16). we found that 2-bromo-4'-nitroacetophenone has antioxidant effect and this effect is dependent on Insulin pathway.

Hydrogen Peroxide Modification of Human Oxyhemoglobin

The effect of H2O2 on the primary structure of OxyHb was studied. Upon treatment of OxyHb with H2O2 ([Heme]/[H2O2] = 1), tryptophan and methionine residues of the beta-chain were modified. Treatment of ApoHb with H2O2 resulted in the modification of histidine and methionine residues in both globin chains. Tryptophan residues were unaffected. Modification of methionine residues in both the beta-chain of OxyHb and ApoHb probably results from the direct oxidation of methionine by H2O2. The modification of histidine residues in ApoHb may be mediated by a metal-catalyzed oxidation system comprised of H2O2 and histidine-bound iron. The H2O2-mediated modification of tryptophan in the OxyHb beta-chain, however, requires the heme moiety.