The major extracellular proteases from the nematophagous fungus Verticillium chlamydosporium and the entomophagous fungus Metarhizium anisopliae, VCP1 and Pr1, respectively, are closely related both functionally and serologically. Antibodies raised against either enzyme cross-reacted with both antigens, suggesting that they have common epitopes. The VCP1 and Prl antisera labelled bovine pancreatic elastase and proteinase K, respectively. Neither antiserum reacted with commercial chymotrypsin. An antiserum to a serine protease from the closely related V. suchlasporium also cross-reacted with VCP1 and Prl. In contrast, a polyclonal antibody to an isoform of Pr1 exclusive to M. anisopliae isolate ME1 failed to recognize Prl from M. anisopliae V245 or VCP1. The N-terminal amino acid sequence of VCP1 revealed similarities with subtilisin-like enzymes from other fungi, but the closest match was with Pr1. The pure enzymes, VCP1 and Prl, failed to hydrolyse mono-aminoacyl-naphthylamide substrates but demonstrated dipeptidyl peptidase activity against Gly-Pro-ßNA and Leu-Ala-ßNA, respectively. These results are discussed in the context of specificity of invertebrate mycopathogens.
FEMS Microbiology Letters (1995) 126 (3) 227-231 [DOI: 10.1111/j.1574-6968.1995.tb07423.x]