Inactivation of horseradish peroxidase by phenol and hydrogen peroxide: a kinetic investigation

Role of the reductant substrates on the inactivation of horseradish peroxidase by m‐Chloroperoxybenzoic acid

“…It differs from other reductant substrates like phenol, azide and phenylhydrazine, because these substances act by generating a reactive radical (8)(9)(10), while the oxidation product of ABTS (a metastable radical cation) does not inactivate the enzyme (7). We have also demonstrated that the ratio between both substrates (reductant substrate/oxidizing substrate) determines the number of catalytic actions made by the enzyme before its inactivation (7).…”

“…In such cases, our suggestion that the reductant substrate/hydroperoxide ratio is the determining factor in the catalytic turnover of peroxidases gains importance. Baynton et al (8) have described the important role of the inactivation process in studies converting hazardous materials into biologically inaccesible and manageable compounds. These authors pointed out the importance of understanding the mechanistic details since it is known that peroxidase catalysis, in certain reaction conditions, does not result in significant enzyme inactivation, while, in other conditions, enzyme inactivation is rapid and frequently non-recoverable.…”

Laccase‐Catalyzed Removal of Diphenylamine from Synthetic Wastewater

“…Klibanov et al, (1983) proposed that, during enzymatic reaction, phenoxyl radicals interact with active site of the enzyme, which results in the inactivation. Irreversible, time-dependent and mechanism-based inactivation was observed in horseradish peroxidase when reductant substrates were present (Baynton et al, 1994). Nakamoto and Machida (1992) have suggested that enzyme inactivation is due to the adsorption of enzyme onto the end-product polymer and the obstruction caused by this for substrate access to the active site.…”

Steady-state kinetics of <i>Roystonea regia</i> palm tree peroxidase

“…Their model, based on studies at high H 2 O 2 concentrations, invokes a further partitioning between these two inactivation pathways and suggests the existence of a catalytic reaction in which H 2 O 2 would be consumed with relatively little harm to the enzyme [64].…”