Effects of Mn2+and Oxalate on the Catalatic Activity of Manganese Peroxidase
Autor: | Serguei L. Timofeevski, Steven D. Aust |
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Rok vydání: | 1997 |
Předmět: |
Inorganic chemistry
Biophysics chemistry.chemical_element Disproportionation Manganese Biochemistry Oxalate chemistry.chemical_compound Reaction rate constant Manganese peroxidase Animals Hydrogen peroxide Molecular Biology Oxalates biology Basidiomycota Cell Biology Hydrogen-Ion Concentration Catalase biology.organism_classification Oxygen Kinetics Peroxidases chemistry biology.protein Phanerochaete Cattle Nuclear chemistry Peroxidase |
Zdroj: | Biochemical and Biophysical Research Communications. 239:645-649 |
ISSN: | 0006-291X |
DOI: | 10.1006/bbrc.1997.7453 |
Popis: | Manganese peroxidase from Phanerochaete chrysosporium is an extracellular heme-containing enzyme known to catalyze the oxidation of Mn 2+ to Mn 3+ in a reaction requiring oxalate or another appropriate manganese chelator. We have found that the enzyme can also catalyze a manganese-dependent disproportionation of hydrogen peroxide when a manganese chelator is not included. The catalatic activity was observed in the pH range from 3.0 to 8.5, and the apparent second-order rate constant for catalatic reaction was about 2 × 10 5 M −1 s −1 at pH 4.5 to 7.0 at 25°C. Oxalate inhibited oxygen production by increasing the apparent K m for Mn 2+ for catalatic activity from micromolar to millimolar levels and facilitating peroxidase activity. Catalase-type function was recovered by excess of Mn 2+ in the presence of oxalate. We propose that catalatic activity may protect the enzyme from inactivation by hydrogen peroxide in an environment where free oxalate may be limited. |
Databáze: | OpenAIRE |
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