الفهرس 
NTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
L-asparaginase is a critical enzyme that plays a pivotal role in depriving cancer cells of an essential amino acid, asparagine, leading to their impaired growth and survival. Asparaginase catalyzes the hydrolysis of asparagine into aspartic acid and ammonia. While most normal cells can synthesize asparagine, certain cancer cells, particularly those of acute lymphoblastic leukemia (ALL), are unable to produce it, relying solely on external sources. The selective vulnerability of cancer cells to asparagine deprivation makes asparaginase an effective anti-cancer agent. It is commonly used in the treatment of ALL, where it helps to achieve remission by targeting leukemic cells specifically. Additionally, it has shown efficacy in other hematological malignancies and solid tumors, albeit to a lesser extent. Moreover, Asparaginase can modulate immune responses, potentially enhancing anti-tumor immunity. It has been suggested that asparagine depletion may affect immune cell function and cytokine production, contributing to its anti-cancer effects beyond mere metabolic deprivation. However, asparaginase is often employed as part of combination chemotherapy regimens for cancer treatment. Its unique mechanism of action complements other anti-cancer agents, leading to synergistic effects and improved treatment outcomes. Moreover, L-asparaginase has gained increased awareness of its anticarcinogenic potential. The treatment of acute lymphoblastic, Hodgkin’s disease, acute myeloid leukemia, acute myelomonocytic leukemia, chronic lymphocytic leukemia, reticulosarcoma, the treatment of lymphosarcoma, and melanosarcoma are among the important uses of the L-asparaginase enzyme.L-asparaginase is an interesting enzyme with important applications in the pharmaceutical and food industries. However, its use in these industries requires certain characteristics to ensure safety for human use. As a chemotherapy agent, in addition to adverse effects such as hypersensitivity and deactivation of the immune system, effective activity is also required.The current study has demonstrated that soils are a rich source of L-asparaginase-producing fungi, with Aspergillus fumigate isolated from Egyptian soil having the capacity to produce large amounts of the enzyme. L-asparaginase could be purified in just two steps while maintaining high enzyme activity. This enzyme has many excellent qualities that make it highly valuable to be used as a potent anticancer agent, such as high catalytic activity over a wide range of temperature and pH, high substrate specificity, maximum activity at close to body temperature, and its considerable thermal and pH stabilities.According to the results of the current investigation, the isolated Aspergillus fumigate used in this study may be a useful potential source of L-asparaginase.The following results were obtained:1. L-asparaginase production peaked at 80 U/ml in 30 minutes of time of incubation.2. The optimum pH for L-asparaginase synthesis was 6.0.3. The activity of l-asparaginase was determined the ideal temperature for enzyme synthesis is 40 °C.4. The activity of l-asparaginase was determined the maximum yield for l-asparaginase is five-day from the incubation of the isolated fungi in the prepared media.5. The production of fungal l-asparaginase was reached to the optimum at (0 -75%) ammonium sulphate concentration.6. L-asparaginase isolated from Aspergillus fumigatus has been purified was tested for activity at various pH values, temperatures and incubation periods. purified l-asparaginase was reached optimal enzyme activity at pH 8.0 with 40 °C temperature & 30 min incubation time. 7. The purified L-asparaginase from Aspergillus fumigatus was significantly affected by the presence of metal ions, inhibitors, organic solvent & surfactants. the enzyme activity was reached maximal levels in the presence of Mg2+ & reached high levels also in the presence of Na+, k+ respectively as metal ions activators for L-asparaginase activity. Also, the enzyme activity enhanced to maximal levels in the presence of organic solvent methanol &reached high levels in the presence of acetone, hexane. The presence of Triton X-100 increased the L-asparaginase as surfactant.8. The MIC of L-asparaginase was1.25 mg/mL against bacterial growths of Bacillus cereus.9. HepG-2 liver cancer cells treated with purified L-asparaginase concentrations (50 μg/ml).10. L-asparaginase shows the highest anticancer effect with IC50 of 1.724 g/ml. Conclusions from the current study, we can conclude that, this study not onlyhighlights the abundance of L-asparaginase-producing fungi in soil but also sheds light on the exceptional capabilities of Aspergillus fumigatus in terms of enzyme production and its potential applications in medicine and food industries. The efficient purification process and potent antimicrobial activity further underscore the significance of Aspergillus fumigatus as a valuable source of L-asparaginase with promising therapeutic potential.