Thimet oligopeptidases (EC 3.4.24.15), also known as TOPs, are a type of M3 metallopeptidases. These enzymes can be found in animals and plants, showing distinctive functions. In animals and humans, they are involved in the degradation of peptides, such as bradykinin, neurotensin, angiotensin I, and Aβ peptide, helping to regulate physiological processes. In plants, their role is related to the degradation of targeting peptides and the immune response to pathogens through Salicylic Acid (SA)-dependent stress signaling. In Arabidopsis thaliana—recognized as a model plant for scientific studies—two thimet oligopeptidases, known as TOP1 and TOP2, have been identified as targets for salicylic acid binding in the plant. These TOP enzymes are key components to understand the SA-mediated signaling where interactions exist with different components and most of the pathways are unknown.