title: Biochemical characterization of a novel L-Asparaginase with low glutaminase activity from Rhizomucor miehei and its application in food safety and leukemia treatment.
abstract: A novel fungal gene encoding the Rhizomucor miehei l-asparaginase (RmAsnase) was cloned and expressed in Escherichia coli. Its deduced amino acid sequence shared only 57% identity with the amino acid sequences of other reported l-asparaginases. The purified l-asparaginase homodimer had a molecular mass of 133.7 kDa, a high specific activity of 1,985 U/mg, and very low glutaminase activity. RmAsnase was optimally active at pH 7.0 and 45°C and was stable at this temperature for 30 min. The final level of acrylamide in biscuits and bread was decreased by about 81.6% and 94.2%, respectively, upon treatment with 10 U RmAsnase per mg flour. Moreover, this l-asparaginase was found to potentiate a lectin's induction of leukemic K562 cell apoptosis, allowing lowering of the drug dosage and shortening of the incubation time. Overall, our findings suggest that RmAsnase possesses a remarkable potential for the food industry and in chemotherapeutics for leukemia.
authors.affiliation: Bioresource Utilization Laboratory, College of Engineering, China Agricultural University, Beijing, China.
authors.forename: Linhua
authors.initials: L
authors.lastname: Huang
authors.forename: Yu
authors.initials: Y
authors.lastname: Liu
authors.forename: Yan
authors.initials: Y
authors.lastname: Sun
authors.forename: Qiaojuan
authors.initials: Q
authors.lastname: Yan
authors.forename: Zhengqiang
authors.initials: Z
authors.lastname: Jiang
mesh_terms: D000970:Antineoplastic Agents / Q000378:metabolism; D017209:Apoptosis; D001215:Asparaginase / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects*; D003001:Cloning, Molecular; D004271:DNA, Fungal / Q000737:chemistry / Q000235:genetics; D004795:Enzyme Stability; D004926:Escherichia coli / Q000235:genetics; D059022:Food Safety / Q000379:methods*; D015870:Gene Expression; D005972:Glutaminase / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D037102:Lectins / Q000378:metabolism; D007938:Leukemia / Q000628:therapy*; D008969:Molecular Sequence Data; D008970:Molecular Weight; D055503:Protein Multimerization; D020103:Rhizomucor / Q000201:enzymology* / Q000235:genetics; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D013696:Temperature
chemical_list: D000970:Antineoplastic Agents; D004271:DNA, Fungal; D037102:Lectins; D001215:Asparaginase; D005972:Glutaminase