In silico and in vitro evaluation of compatibility between papain and agricultural pesticides

Brazil is a major consumer of pesticides, which raises concerns in the context of One Health. In this sense, new biotechnological alternatives for pest and disease control are fundamental. The use of relevant biomolecules, such as papain, a cysteine protease present in Carica papaya latex, has shown great potential. In this context, this study investigated in silico, through molecular docking with 130 pesticides authorized by MAPA and through experimental assays, the interactions between pesticides and papain, in addition to evaluating the combined action on Tenebrio molitor larvae. Metaflumizone and etiprole were selected for biochemical analysis, with proteolytic activity determined by the caseinolytic method and the effects on larvae evaluated in vitro. By docking analysis, metaflumizone presented the lowest binding energy (−8.6 kcal mol−1), indicating high affinity for the active site; however, in experimental tests, there was no significant change in papain activity (p > 0.05). On the other hand, etiprole reduced enzymatic activity by 64%, but only at a concentration four times higher than that used in the spray (p < 0.01).