الفهرس 
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Abstract
The enzyme L-asparaginase catalyzes the conversion of L-asparagine to aspartic acid and ammonia. L-asparagine is a source of essential amino acid necessary for the growth of leukemic cells in higher amounts. depriving the leukemic cell from circulating asparagine, which leads to cell death. In this study, 34 randomly selected streptomycetes isolates were discovered in soil, marine water, sediment, and other environments. Using a qualitative fast plate assay, they were tested for ASNase production, and 9 of them produced a substantial ASNase pink hue. Streptomyces albidoflavus was discovered by 16S rRNA gene sequencing in a promising strain known as G9. A pH of 7.0, an incubation temperature of 30 °C, and the use of glucose and peptone as the carbon and nitrogen sources, respectively, all contributed to the highest levels of AsNase synthesis. The molecular weight of the purified ASNase was determined to be 84 kDa by SDS-PAGE analysis, and the final specific activity was reported to be 21.69 U/mg. At pH levels of 8.5 and temperatures of 40 C, respectively, the isolated enzyme showed its highest activity and stability. The isolated enzyme has a Km of 7.2 mM and a Vmax of 71.27 U/ml, respectively. The isolated ASNase’s antineoplastic activity validated ample toxicity toward HCT-116 cells (IC50 49.0 µg/mL), which was lower than that shown against MCF-7 (IC50 18.70 µg/mL) and HepG2 cells (IC50 20.3 µg/mL). The isolation of Streptomyces albidoflavus, which generates a glutaminase-free AsNase and may be a possible candidate for further pharmacological solicitation as an anticancer medicine; also the soil and seawater constitute a promising biological reservoir, according to our results.