Avaliação da hidrólise da amoxicilina por Penicilina G acilase

Abstract

Water is a natural, finite, vulnerable and indispensable resource for life. However, the presence of chemical substances in the aquatic environment has been increasingly frequent, including in water for public and industrial supply, suggesting an imminent risk to human and environmental health. Among the most common chemical substances in the aquatic environment are pharmaceuticals, including beta-lactam antibiotics, the most prescribed class of antibiotics with the most clinical indications, such as amoxicillin. Therefore, the objective of this work was to evaluate the variables that influence the enzymatic hydrolysis of amoxicillin and its kinetics. For this, a central composite planning was used, in which the variables were analyzed: initial concentration of amoxicillin, temperature and pH in the hydrolysis of the antibiotic. The range of values of the variables studied was 0.16 to 1.84 (% w/v) for the initial concentration of amoxicillin; 26 to 49 °C; and pH 5.32 to 8.68. For kinetic analysis, the Levenberg-Marquardt numerical method was used to estimate the optimal values of the kinetic parameters of the Michaelis-Menten equation, in order to adjust it to the experimental data. However, the initial substrate concentration was the variable that most influenced the hydrolysis of amoxicillin, and also the quadratic temperature and pH. Furthermore, the maximum PGA activity was observed at intermediate values of temperature and pH, 38 °C and 7.0 respectively. Finally, the Michaelis-Menten model represented well the kinetics of the reaction, whose parameter values indicated a good affinity of the enzyme for amoxicillin.