Metabolic activation of m-phenylenediamine to products mutagenic in Salmonella typhimurium by medium isolated from tobacco suspension cell cultures.

Both tobacco cells in suspension and the medium recovered from the suspension cultures (TX1MX) activated the aromatic amine m-phenylenediamine (m-PDA) into a product that was mutagenic in Salmonella typhimurium TA98 and YG1024. Medium recovered from stationary-phase tobacco cell cultures exhibited the highest level of m-PDA activation. No cytochrome P-450 was detected in the activating medium. A high molecular weight matrix having the highest m-PDA activating capacity and associated with a substantial fraction of the total peroxidase activity was isolated by Centricon-100 ultrafiltration of TX1MX. The data suggest that the peroxidases present in the recovered cell culture medium or in the high molecular weight matrix are responsible for the plant activation of m-PDA.