Ping–pong mechanism
Application. o-Phenylenediamine Free Base is a peroxidase substrate suitable for use in ELISA procedures. The substrate produces a soluble end product that is orange-brown in color and can be read spectrophotometrically at 450 nm. The OPD reaction may be stopped with 3 N HCl or 3 M H 2 SO 4 and read at 492 nm. Synthesis, spectroscopic investigations, antimicrobial and DNA binding studies of a new charge transfer complex of o-phenylenediamine with 3,5-dinitrosalicylic acid. Khan IM, Ahmad A, and Ullah MF Spectrochim. Abstract. The hydrogen peroxide-oxidation of o-phenylenediamine (OPD) catalyzed by horseradish peroxidase (HRP) at 37 °C in 50 mM phosphate buffer (pH 7.0) was studied by calorimetry. The apparent molar reaction enthalpy with respect to OPD and hydrogen peroxide were −447 ± 8 kJ mol −1 and −298 ± 9 kJ mol −1, respectively. Oxidation of OPD by H 2 O 2 catalyzed by HRP (1.25 nM) at pH 7.0 and 37 °C follows a ping–pong mechanism. o-Phenylenediamine is an organic compound with the formula C 6 H 4 (NH 2) 2. This aromatic diamine is an important precursor to many heterocyclic compounds. It is isomeric with m-phenylenediamine and p-phenylenediamine, and is commonly referred to as OPD.
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mechanism of of o-phenylenediamine