A zinc-dependent enzyme isolated from a strain of the bacterium Pseudomonas. Because glucarpidase rapidly hydrolyzes methotrexate into inactive metabolites, it may be useful as a rescue agent for methotrexate-induced nephrotoxicity. In antibody-directed enzyme prodrug therapy (ADEPT), this agent is conjugated with an antibody that binds to a specific tumor cell type, allowing for glucarpidase-catalyzed activation of a co-administered prodrug at the site of the tumor.