A systematic review of recent trends in research on therapeutically significant L-asparaginase and acute lymphoblastic leukemia.

L-asparaginases are mostly obtained from bacterial sources for their application in the therapy and food industry. Bacterial L-asparaginases are employed in the treatment of Acute Lymphoblastic Leukemia (ALL) and its subtypes, a type of blood and bone marrow cancer that results in the overproduction of immature blood cells. It also plays a role in the food industry in reducing the acrylamide formed during baking, roasting, and frying starchy foods. This importance of the enzyme makes it to be of constant interest to the researchers to isolate novel sources. Presently L-asparaginases from E. coli native and PEGylated form, Dickeya chrysanthemi (Erwinia chrysanthemi) are in the treatment regime. In therapy, the intrinsic glutaminase activity of the enzyme is a major drawback as the patients in treatment experience side effects like fever, skin rashes, anaphylaxis, pancreatitis, steatosis in the liver, and many complications. Its significance in the food industry in mitigating acrylamide is also a major reason. Acrylamide, a potent carcinogen was formed when treating starchy foods at higher temperatures. Acrylamide content in food was analyzed and pre-treatment was considered a valuable option. Immobilization of the enzyme is an advancing and promising technique in the effective delivery of the enzyme than in free form. The concept of machine learning by employing the Artificial Network and Genetic Algorithm has paved the way to optimize the production of L-asparaginase from its sources. Gene-editing tools are gaining momentum in the study of several diseases and this review focuses on the CRISPR-Cas9 gene-editing tool in ALL.

Toxicity Analysis of Recombinant L-asparaginase I and II in Zebrafish.

L-asparaginases are extensively applied in the treatment of Acute Lymphoblastic Leukemia (ALL). The treatment regime of ALL consists of asparaginase from E. coli or Erwinia. The survival rate post-chemotherapy has increased to < 90% in recent years. Asparaginase therapy has also resulted in numerous toxicities to patients receiving therapy. This study demonstrates the reaction of normal cells of Danio rerio to asparaginase therapy. L-asparaginase I and II used in the present study are from two probiotic Lactobacillus species in comparison with a commercial L-asparaginase of E. coli origin. Zebrafish adults were injected with 2500 U/kg body weight of L-asparaginase treatments. The expression of SOD 2, CAT, GST, GTP BP3, FADS2 were analyzed with EF1α as house-keeping gene. The p value obtained proves that the data are significant. The histology of the L-asparaginase I treated fishes showed dilated sinusoids in the liver and pseudocyst in the pancreas. The L-asparaginase II and commercial asparaginase showed no pathology.

Recombinant l-Asparaginase II from Lactobacillus casei subsp. casei ATCC 393 and Its Anticancer Activity.

l-asparaginases from bacterial origin are employed extensively in leukemic treatment and food industry. The present study focuses on the characterization of the recombinant l-asparaginase II from Lactobacillus casei subsp. casei ATCC 393 cloned into Escherichia coli expression system and purified using Ni-NTA chromatography. The recombinant l-asparaginase as a monomer had a molecular weight of 35 kDa. The enzyme was active from 10 to 80 °C with the optimum at 40 °C. The enzyme retained its activity at 28 °C and 37 °C up to 24 h. The enzyme had optimum pH of 6 and retained 50% activity till 18 h. The Km of the recombinant enzyme was 0.01235 mM and Vmax 1.576 mM/min. The half life of recombinant l-asparaginase II in human serum was 44 h and trypsin was for 15 min. The LC-MS/MS analysis revealed the molecular weight of 35,050 and pI of 5.64. The secondary structure prediction using CD spectroscopy for the recombinant enzyme showed 33.5% α-helix, 66.5% turn and 0% ß sheets. The cytotoxicity of the recombinant enzyme was analysed against MOLT 3, Jurkat E6.1 and K-562 with the IC 50 value of 30, 62.5 and 50 µg/ml.

Functional characterization of a putative endoglucanase gene in the genome of Zymomonas mobilis.

The sequence of the putative endoglucanase gene ZMO1086 in the genome of Zymomonas mobilis showed a 40% similarity with known bacterial endoglucanase genes. The upstream region of this putative gene revealed the presence of characteristic promoter (-10 and -35 regions) and a Shine-Dalgarno region. The putative endoglucanase gene was poorly expressed from the native promoter of Z. mobilis and therefore the putative endoglucanase gene was cloned and expressed in Escherichia coli BL21. The overexpressed gene product CelA was purified to homogeneity and the optimal activity was observed at 30 degrees C and pH 6 respectively.