The present invention provides enzymes capable of hydrolysing organophosphate (OP) molecules. In particular, the invention provides a phosphotriesterase enzyme identified from an Agrobacterium radiobacter strain isolated from soil that hydrolyses OP pesticides, and the gene encoding that enzyme. The invention also provides mutants of the identified phosphotriesterase enzyme which have altered substrate specificity. The use of these enzymes in bioremediation strategies is also provided.
