Biochemical characterization of genome derived L-asparaginase from eurypsychrophilic Iodobacter sp. PCH194 for therapeutic and food applications

L-asparaginase is an important therapeutic biomolecule, used to treat lymphocytic leukemia. In the present study, Iodobacter sp. PCH194 genome was mined for new L-asparaginase (Id-ASNase II). In silico analysis including amino acid composition and pI revealed its sequence-based novelty and phylogenetic closeness to the commercial bacterial L-asparaginases. Subsequently, the gene was successfully cloned and overexpressed in Escherichia coli (E. coli BL21 DE3). The monomeric molecular weight of Id-ASNase II was 38 kDa with a native size of 150 kDa. Maximum L-asparaginase activity (80 U mg^{− 1}) was achieved in 25 mM Tris-HCl buffer (pH 8.2) at 37 °C after 10 min of incubation. The enzyme was active in wide pH (5.0–11.0) and temperature ranges (4–70 °C). The half-life (t_1/2) of the enzyme at 37 °C was 13.54 h, whereas K_m, V_max, k_cat, and k_cat/K_m were 1.2 mM, 128 µmoles min^{− 1}, 82 s^{− 1}, and 63.1 s^{− 1} mM^{− 1}, respectively. Id-ASNase II exhibited cytotoxicity against cancer cell line K562 (IC₅₀ value 0.4 U mL^{− 1}) leading to cell cycle arrest in the G2/M phase after treatment. Furthermore, 10 U Id-ASNase II led to a 57% acrylamide reduction in potato chips. Thus, the study discovered and characterized Id-ASNase II with potential applications for treating leukemia and food processing.