Deciphering the Catalytic Triad Mechanism in Serine Proteases: A Comparative Study

Understanding enzyme mechanisms is crucial for advancing biochemical applications in medicine and industry. This study focuses on the catalytic triad mechanism in serine proteases, a pivotal group of enzymes involved in numerous physiological processes. The objective was to compare the catalytic efficiency and substrate specificity of serine proteases across different species. Using site-directed mutagenesis and kinetic analysis, we evaluated the catalytic rates (k_cat) and substrate affinity (K_m) of chymotrypsin, trypsin, and elastase. Our findings revealed that chymotrypsin exhibited the highest catalytic efficiency with a k_cat/K_m value of 5.8 × 10^5 M^-1s^-1, compared to trypsin and elastase, which showed values of 4.2 × 10^5 M^-1s^-1 and 3.5 × 10^5 M^-1s^-1, respectively. These differences were attributed to variations in the hydrogen bonding network within the catalytic triad. Furthermore, molecular dynamics simulations highlighted the role of dynamic conformational changes in substrate recognition. The study concludes that the catalytic triad, despite its conserved nature, can exhibit significant mechanistic diversity, providing insights into enzyme evolution and potential for designing enzyme inhibitors. Our work lays a foundation for future explorations into enzyme engineering for therapeutic purposes.