Faster and sensitive zymographic detection of oxidases generating hydrogen peroxide. The case of diamine oxidase.

The existing zymography method for the detection of diamine oxidase (DAO) activity has been improved by a new staining procedure with the aim to ameliorate its sensitivity. Both procedures used SDS-PAGE gels containing uniformly distributed entrapped peroxidase (that wouldn't migrate during electrophoresis). The new approach with 3,5-dichloro-2-hydroxybenzenesulfonate (DCHBS) as peroxidase substrate and with 4-amino-antipyrine as color stabilizer allows a more sensitive detection of DAO when compared to the previously reported o-phenylenediamine (o-PDA) as peroxidase substrate. The newly improved method appears faster, simple and environmentally friendly. It can be used for most of oxidases releasing hydrogen peroxide as reaction product.