Description
Peroxidases (EC number 1.11.1.x) are a large family of enzymes that typically catalyze a reaction of the form:ROOR' + electron donor (2 e−) + 2H+ → ROH + R'OH. For many of these enzymes the optimal substrate is hydrogen peroxide, but others are more active with organic hydroperoxides such as lipid peroxides. Peroxidases can contain a heme cofactor in their active sites, or alternately redox-active cysteine or selenocysteine residues.
Abbr
Peroxidase, Native (Horseradish)
Product Overview
Peroxidase (HRP) is a hemoprotein catalyzing the oxidation by hydrogen peroxide of a number of substrates such as ascorbate, ferrocyanide, cytochrome c and the leuco form of many dyes. A soluble , dialyzed, lyophilized powder. RZ 1.0.
Form
A soluble , dialyzed, lyophilized powder
Enzyme Commission Number
EC 1.11.1.7
Activity
> 85 units per mg dry weight
Molecular Weight
40 kDa (Maehly 1955).
Isoelectric point
7.2 (Maehly 1955).
Composition
Seven isozymes have been described by Shannon et al. (1966);Kay et al. (1967); and Strickland et al. (1968). See also Delincée and Radola (1975) and Shih et al. (1971). All contain photohemin IX as prosthetic group. Neutral and amino sugars account for approximately 18% of the enzyme. Weinryb (1966) indicates that the "active site" involves apoprotein as well as the heme group. See also Lanir and Schejter (1975). Dolman et al. (1975) have reported on the formation of Compound I. See also Dunford et al. (1975), Santimone (1975) and Stillman et al. (1975).
Specificity
The enzyme exhibits a high specificity. Activity is observed with H2O2, MeOOH, and EtOOH (Maehly and Chance 1954). See also Chmielnicka et al. (1971) and Morrison and Bayse (1973).
Unit Definition
One Unit decomposes 1µmole of H2O2 per minute at 25°C, pH 7.0 using aminoantipyrine and phenol.
Optimum pH
7.0 (Maehly 1955).
Stability
The enzyme is quite stable. As a lyophilized powder, it may be stored several years refrigerated.
Inhibitors
Horseradish peroxidase is reversibly inhibited by cyanide and sulfide at a concentration of 10-5 M (Theorell 1951).
Pathway
C-MYB transcription factor network, organism-specific biosystem; Folate Metabolism, organism-specific biosystem; IL23-mediated signaling events, organism-specific biosystem; Phagosome, organism-specific biosystem; Phagosome, conserved biosystem; Selenium Pathway, organism-specific biosystem; Transcriptional misregulation in cancer, organism-specific biosystem
Function
chromatin binding; heme binding; heparin binding; metal ion binding; oxidoreductase activity; peroxidase activity
Synonyms
EC 1.11.1.7; Peroxidase; lactoperoxidase; guaiacol peroxidase; plant peroxidase; Japanese radish peroxidase; horseradish peroxidase (HRP); soybean peroxidase (SBP); extensin peroxidase; heme peroxidase; oxyperoxidase; protoheme peroxidase; pyrocatechol peroxidase; scopoletin peroxidase; Coprinus cinereus peroxidase; Arthromyces ramosus peroxidase
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