DETERMINATION OF MANGANESE PEROXIDASE-ACTIVITY WITH 3-METHYL-2-BENZOTHIAZOLINONE HYDRAZONE AND 3-(DIMETHYLAMINO)BENZOIC ACID

This method was proposed earlier for measuring glucose in a peroxidase -glucose oxidase system but has not been studied for determination of manganese peroxidase (MnP) activity. The assay is based on the oxidati ve coupling of 3-methyl-2-benzothiazolinone hydrazone (MBTH) and 3-(di methylamino)benzoic acid (DMAB). The reaction of MBTH and DMAB in the presence of H2O2, Mn2+, and MnP gives a deep purple-blue color with a broad absorption band with a peak at 590 nm. The extinction coefficien t is high (53,000 M(-1) cm(-1)), so low MnP activities can be detected . Lignin peroxidase and laccase, usually present in cultures of white rot fungi, gave little or no interference at the concentrations tested . However, slight interference from very high LiP activity may occur a t very low MnP activity. (C) 1994 Academic Press, Inc.