In the realm of enzyme catalysis, the hallmark is the accelerated pace of enzymatic reactions compared to their counterparts in reference aqueous solutions. To comprehensively assess the catalytic influence of the enzyme environment, it is essential to consider the corresponding reaction in a reference solution. The Empirical Valence Bond (EVB) approach, as outlined in section 2.2, stands as a favored computational method in enzymology. Its appeal lies in its computational efficiency and its ability to seamlessly incorporate parameters relevant to the reference reaction. This paper aims to shed light on the catalytic mechanism governing the esterolysis of para-nitrophenol acetate (p-NPA) by human glucagon fibrils, using it as an illustrative model of catalysis, with a specific focus on the acylation step involving proton transfer and nucleophilic attack (PT-NA). Our investigation employs PDLD/S-LRA-2000 method, detailed in section 2.1, for extensive binding energy calculations and qualitative assessments of catalytic activity in the studied system. We employed the EVB method for rigorous elucidation of the reaction mechanism. For calibration of the EVB treatment, it is imperative to evaluate the thermodynamic and kinetic parameters of the reference reaction. In this study, we derived the EVB parameters of the reference reaction in water through a combination of experimental and ab-initio data, as previously reported in our works. By combining these computational approaches, our work offers a deeper understanding of the catalytic mechanisms at play within glucagon amyloid fibrils.