Description_x000D_ Application_x000D_ Inactivated peroxidase is used to study regeneration of inactivated peroxidase enzymes. It has been used to study the mechanism of peroxidase solubilization and it is used to study antitumor activity of immobilized peroxidase systems. It may be used for developing differential staining techniques in nerve tissue preparations._x000D_ Biochem/physiol Actions_x000D_ HRP readily combines with hydrogen peroxide (H2O2) and the resultant [HRP-H2O2] complex can oxidize a wide variety of hydrogen donors. The optimal pH is 6.0-6.5 and the enzyme is most stable in the pH range of 5.0-9.0. HRP can be conjugated to antibodies by several different methods that include the use of glutaraldehyde, periodate oxidation, disulfide bonds, and also via amino- and thiol-directed cross-linkers. It is smaller and more stable than the enzyme labels, β-galactosidase and alkaline phosphatase. Hence, it is the most desired label. Also, its glycosylation leads to lower non-specific binding. It is also used for the determination of glucose and peroxides in solution. Sodium azide, cyanide, L-cystine, dichromate, ethylenethiourea, hydroxylamine, sulfide, vanadate, p-aminobenzoic acid, and ions such as Cd2+, Co2+, Cu2+, Fe3+, Mn2+, Ni2+, and Pb2+ are found to inhibit the enzyme activity._x000D_ Inactivated peroxidase reacts with goat and rabbit anti-peroxidase. It may be reactivated various methods such as heating._x000D_ Unit Definition_x000D_ One unit will form 1.0 mg purpurogallin from pyrogallol in 20 sec at pH 6.0 at 20°C._x000D_ Preparation Note_x000D_ Prepared from Type VI horseradish peroxidase by a modification of the method of Teale.