Abstract: We have studied the regulation of the extracellular chymoelastase protease (Pr1) of Metarhizium anisopliae, an enzyme involved in the penetration of insect cuticle by Metarhizium and other entomopathogenic fungi. We report here the isolation and characterization of a Pr1 cDNA clone with a full length insert. Pr1 is synthesized as a large precursor (40.3 kDa) containing a signal peptide and a propeptide and the mature protein is predicted to have a relative molecular mass of 28.6 kDa. The primary structure of Pr1 shares extensive homology (30-60%) with enzymes of the subtilisin subclass of the serine endopeptidases and the serine, histidine and aspartyl components of the active site in subtilisins are preserved. The genes coding for chymoelastase or slightly altered versions thereof, can be used to transform various organisms (i.e. fungi, viruses, plants, bacteria, etc.) such that the transformed organisms are capable of producing chymoelastase in recoverable quantities.