Ascorbate peroxidases are haem proteins that efficiently scavenge H2O2 in the cytosol and chloroplasts of plants. Database analyses retrieved 52 expressed sequence tags coding for Arabidopsis thaliana ascorbate peroxidases. Complete sequencing of non-redundant clones revealed three novel types in addition to the two cytosol types described previously in Arabidopsis. Analysis of sequence data av...

The circular dichroism spectra of native and recombined vinyl-(protojhematin horseradish peroxidase are identical, which confirms the proper position of the reintroduced group. The same observation and conclusion applies to the light absorption spectra. Circular dichroism and light absorption spectra of seven artificial peroxidases, prepared from apoperoxidase and 2,4substituted hematins, have ...

We have obtained oxygen-17 (17O) nuclear magnetic resonance (NMR) spectra of C17O ligands bound to ferrous horseradish peroxidase isozyme A, isozyme C, and ferrous chloroperoxidase, as a function of pH. Our results show that the peroxidases exist in two distinct states, the acidic and alkaline forms, which undergo reversible acid-base-induced transitions characterized by a single pK value. The ...

Photosynthesis is a highly robust process allowing for rapid adjustment to changing environmental conditions. The efficient acclimation depends on balanced redox metabolism and control of reactive oxygen species release which triggers signaling cascades and potentially detrimental oxidation reactions. Thiol peroxidases of the peroxiredoxin and glutathione peroxidase type, and ascorbate peroxida...

Microbial manganese peroxidases (MnPs) are ligninolytic enzymes primarily responsible for degrading lignin, but they also capable of dyes, organic pollutants, and emerging contaminants in wastewater. They have been isolated characterized from many white-rot fungi few bacteria. For microbial MnPs, the optimum pH range is between 3.5 9.0; temperature 25°C 70°C. Their molecular weights 25 kDa 68 k...

Peroxidases are enzymes that utilize hydrogen peroxide to oxidize substrates. A histidine residue on the proximal side of the haem iron ligates most peroxidases. The various oxidation states and ligand complexes have been spectroscopically characterized. HRP-I is two oxidation states above ferric HRP. It contains an oxoferryl (= oxyferryl) iron with a pi-radical cation that resides on the haem....