Critical view on the monochlorodimedone assay utilized to detect haloperoxidase activity

Haloperoxidase activity guided protein purification from the cyanobacterium Fischerella ambigua revealed the isolation of a protein positive in the monochlorodimedone-assay, but an involvement in halogenating processes could not be verified. Our data indicate that the reaction of MCD with proteins of the cytochrome c - family leads to unspecific products giving false positive results.