Este trabalho descreve a elaboração de uma aula prática simples e de fácil realização para uso em aulas de Bioquímica. A prática consiste na utilização de um espectrofotômetro na faixa de luz visível para obtenção da constante de associação do complexo formado pelo equilíbrio da interação de um ligante (vermelho de fenol) com uma proteína (albumina sérica bovina, BSA). O parâmetro permite o cálculo da variação de energia de Gibbs da interação, e sua comparação com a literatura, permitindo ao aluno vivenciar na prática conceitos abstratos de difícil apropriação, tais como as quantidades termodinâmicas elencadas. A prática pode ser aplicada no período convencional de uma aula prática (60 min), incluindo a coleta de dados e quantificação dos parâmetros.

Insects overcome the action of natural protease inhibitors (PIs) due to evolutionary adaptations through endogenous proteolysis and reprogramming proteases. Insect adaptations complicate the formulation of IP‐based crop protection products. However, small peptides designed based on the active site of enzymes have shown promising results that could change this scenario. GORE1 and GORE2 are designed tripeptides that reduce the survival of Anticarsia gemmatalis when ingested orally. In this article, the stability and ability of the peptides to bind trypsin‐like enzymes of A. gemmatalis were evaluated by molecular dynamics (MD) simulations. The ability of the peptides to inhibit trypsin‐like enzymes in vivo was compared with the SKTI protein by feeding A. gemmatalis larvae at different concentrations, followed by an inhibition persistence assay. During the MD simulation of enzyme–ligand complexes, both peptides showed a small variation of root‐mean‐square deviation and root‐mean‐square fluctuation, suggesting that these molecules reach equilibrium when forming a complex with the trypsin‐like enzyme. Furthermore, both peptides form hydrogen bonds with substrate recognition sites of A. gemmatalis trypsin‐like enzyme, with GORE2 having more interactions than GORE1. Larvae of A. gemmatalis exposed to the peptides and SKTI showed a similar reduction in proteolytic activity, but the persistence of inhibition of trypsin‐like enzyme was longer in peptide‐fed insects. Despite their size, the peptides exhibit important active and substrate binding site interactions, stability during complex formation, and steadiness effects in vivo. The results provide fundamental information for the development of mimetic molecules and help in decision‐making for the selection of delivery methods for larger‐scale experiments regarding similar molecules.

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