Abstact

L-asparaginase catalyzes the hydrolysis of L-asparagine into aspartic acid and ammonia and is found in animals, plants, and microorganisms. Microbial sources are preferred for large-scale production due to their efficiency and ease of cultivation. In this study, we produced and characterized a recombinant L-asparaginase from Bacillus subtilis (Asp-Z). Asp-Z was heterologously expressed in Escherichia coli and purified by affinity chromatography, yielding soluble protein with optimal activity at 55 °C and pH 7.5. The kinetic parameters under these conditions were a Km of 0.47 mM and a Vmax of 52.13 U/mg. Asp-Z was specific for L-asparagine, showing no detectable glutaminase activity, and exhibited antiproliferative effects against hematological cancer cell lines, particularly RAJI and JURKAT, with IC₅₀ values in the micromolar range. In silico analysis revealed distinct immunogenic epitopes between Asp-Z and the commercial E. coli L-asparaginase, suggesting divergent antigenic profiles, whereas crystallographic data revealed a conserved tetrameric fold with a highly flexible active-site loop. Together, these findings highlight Asp-Z as a thermostable, glutaminase-free, and poorly immunogenic enzyme that represents a promising scaffold for optimization through protein engineering toward therapeutic and biotechnological applications.