Syntheses of isodityrosine, dityrosine and related compounds by phenolic oxidation of tyrosine and phenylglycine derivatives using an electrochemical method
The phenolic oxidation of l-tyrosine derivatives by electrolysis and zinc reduction produced the coupling products leading to isodityrosine and dityrosine. The oxidation mode could be controlled by altering halogen substituents (Br or I) at two ortho positions of phenol groups. Additionally, this methodology was applied to 4-hydroxy-d-phenylglycine derivatives, providing the corresponding oxidative
The effects of adding hydrogen peroxide and peroxidase to wheat-flour dough on dityrosine formation and mixing characteristics were investigated. Dityrosine in wheat-flour dough was identified by HPLC with a fluorescence detector and by LC/MS/MS. Formation of dityrosine increased with the addition of hydrogen peroxide, and hydrogen peroxide plus peroxidase, to wheat-flour dough, while the addition of peroxidase had no effect on the amount of dityrosine formed. The mixing curve obtained by a doughgraph changed with the addition of hydrogen peroxide, and hydrogen peroxide plus peroxidase; the peak time was significantly delayed and the dough development time was extended. We found that dityrosine cross-links in wheat-flour dough increased with the addition of peroxidase plus hydrogen peroxide. It is thought that these cross-links can lead to polymerization of the proteins in wheat-flour dough.
A Novel Procedure for Generating both Nitric Oxide and Superoxide in Situ from Chemical Sources at Any Chosen Mole Ratio. First Application: Tyrosine Oxidation and a Comparison with Preformed Peroxynitrite
作者:George R. Hodges、Jasvir Marwaha、Thomas Paul、K. U. Ingold
DOI:10.1021/tx0001272
日期:2000.12.1
presence of CO(2)) using various different ratios of the rates of formation of (*)NO and O(2)(*)(-). The (*)NO/O(2)(*)(-) = 1.0 product profiles are very similar to those of the products derived from equal amounts of (*)NO and O(2)(*)(-) generated at a (*)NO/O(2)(*)(-) ratio of 1.0 from SIN-1 but are very different from those derived frompreformedperoxynitrite. All the experimental results can be explained
Synthesis, ligand binding and biomimetic oxidations of deuterohaemin modified with an undecapeptide residue
作者:Luigi Casella、Michele Gullotti、Luca De Gioia、Enrico Monzani、Francesco Chillemi
DOI:10.1039/dt9910002945
日期:——
sixth iron co-ordination position. The complex exhibits both catalase and peroxidase activity towards reducing substrates in the presence of hydrogen peroxide. In catalytic sulphoxidations of a series of para-substituted thioanisoles, p-XC6H4SMe, by hydrogen peroxide a good correlation has been found between the relative rates and the Hammett σp values, indicating that direct oxygentransferfrom the