Purification and characterization of the cuticle-degrading proteases produced by an isolate of Beauveria bassiana using the cuticle of the predatory bug, Andrallus spinidens Fabricius (Hemiptera: Pentatomidae)

The entomopathogenic fungi-like must penetrate via the integument of an insect to reach the hemocoel. Since proteins are the molecules responsible for integument strength in insects, the proteins must synthesise the cuticle degrading proteases which will then enable the proteases to penetrate. It is important to determine the biochemical properties of these proteases so that fungal virulence can be better understood. In the current study, a recently collected isolate of , namely AM-118, was inoculated in liquid media containing 0.5% of Fabricus cuticle to obtain specific proteases. The crude samples were purified via a three step process using ammonium sulfate, Sepharyl G-100, and DEAE-Cellulose Fast Flow. The results revealed two proteases known as subtilisin-like (Pr1), and trypsin-like (Pr2), with the molecular weights of 105 and 103 kDa. The optimal pH and temperature values were found to be 8 and 35°C for Pr1 and 8 and 40°C for Pr2, respectively. Inhibitors like AEBSF, EDTA, TPCK, and phenanthroline significantly affected proteolytic activities. Here, we reported two fungal proteases by high molecular weight from an Iranian isolate of . These findings will help us to better understand fungal virulence against insects.