Enhancement of Chemiluminescence from the Oxidation of Luminol with Hydrogen Peroxide Catalyzed by Mn(III)‐Microperoxidase 8

Mn(III)‐containing microperoxidase 8 (Mn(III)‐MP8) is an effective catalyst for the cheminluminescent (CL) reaction involving the oxidation of luminol with hydrogen peroxide at high pH. The CL emission was dramatically enhanced by the presence of guanidine hydrochloride or sodium carbonate in the reaction mixture. The enhancement was strongly pH‐dependent, with the most prominent pH at 10. Kinetic studies of the CL reaction have revealed that the enhancement was caused primarily by the significant acceleration of the CL cycle by the enhancer. The CL signal covers several orders of magnitude over a wide concentration range of luminol and hydrogen peroxide. The intense CL of the [Mn(III)‐MP8]‐luminol‐H 2 O 2 system, especially in the presence of the enhancer, will have a great potential for extremely sensitive CL assays.