In the case of 1,10-phenanthroline (1 mm) and EDTA (10 mm), no residual activity could be determined for the peptidase of P. panacis. Both chemicals are metal cation chelators and this indicates that the enzyme most probably belongs to the group of metallopeptidases, in accordance with the literature. Most of the Pseudomonas sp. peptidases described are described as metallopeptidases.