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asparaginase-enzyme
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Biological Removal of Acrylamide Produced During the Baking Process
, M.Sc. Thesis Sharif University of Technology ; Alemzadeh, Iran (Supervisor)
Abstract
In recent year's acrylamide as a suspected substance for tumor growth has been studied. In some researches this topic is mentioned that acrylamide is produced by the reaction of asparagine and natural sugars. This reaction takes place only at very high temperatures during the heating process. The maximum amount of this substance is determined in fried potato products. In this study, a response surface methodology (RSM) 5-level-3-factor face centre central-composite design (FCCCD) was applied to envestigate the effects of asparaginase (300-900 U/kg of flour), baking temperature (230-280 °c) and baking time (13-16 min) on acrylamide (AA) formation in yeast-leavened wheat bread and...
Synthesis and Structural Activity Relationship (SAR) of Novel Pyridazine-based Inhibitors for Inhibition of Amyloid Fibril Formation, and Biosynthesis and Optimization of L-AsparaginaseII Enzyme for Hydrolysis of Non-Native Substrate
, M.Sc. Thesis Sharif University of Technology ; Kalhor, Hamid Reza (Supervisor)
Abstract
After proteins, one of the important biological macromolecules, are synthesized by ribosomes,they automatically reach their own special 3-D structure. This native structur or better known as folded state is what determines the function of a protein. In some situations, the proteins become misfolded leading to its lack of biological function through aggregation or fibril formation known as "amyloid". The amyloid fibrils have been shown to be a causative factor in nerve decay such as Alzheimer's. Therefore, inhibition of amyloid formation using different approaches such as synthetic organic and natural compounds has, recently, been under spotlight. A pyridazine basedcompound (RS-0406) has...
Directed Evolution of the Asparaginase Enzyme to Alter Substrate Specificity
, M.Sc. Thesis Sharif University of Technology ; Kalhor, Hamid Reza (Supervisor)
Abstract
Asparagainase is a therapeutic enzyme which has been a subject of research for decades. The enzyme catalyzes the hydrolysis of the amide group in asparagine and similar amides. Altering the substrate specificity and stabilization of this enzyme can increase its therapeutic properties. Moreover, asparaginases may be evolved to catalyze the hydrolysis of other similar compounds. These can be achieved through directed evolution and computational methods.In this study, the gene encoding L-asparaginase II enzyme from E. coli was amplified by polymerase chain reaction (PCR) and was cloned into an expression vector. The recombinant protein was expressed by an appropriate host secreting the...
Investigate Kinetic Parameters of L-Asparaginase Ii as Well as its Performance in Organic Reactions and Modifying the Enzyme Through Directed Evolution for Carrying Out Promiscuous Reactions
, M.Sc. Thesis Sharif University of Technology ; Kalhor, Hamid Reza (Supervisor)
Abstract
L-asparaginase II is an amidohydrolase which hydrolyzes L-asparagine to furnish L-aspartic acid and ammonia. The enzyme has played an important role for 40 years in treating cancer in persons with juvenile leukemias or lymphomas. Furthermore, the enzyme has become important in food industries and biosensors technology.In this study, the expression of recombinant L-asparaginase II in E. Coli was optimized and the purification of this enzyme from growth culture was carried out with nickel-charged affinity resin. Afterwards, the activity, and kinetic parameters of purified recombinant L-asparaginase II including Km, kcat, Vmax, and enzyme efficiency were measured.In the next step, random...
Optimization of l-asparaginase immobilization onto calcium alginate beads
, Article Chemical Engineering Communications ; Volume 204, Issue 2 , 2017 , Pages 216-220 ; 00986445 (ISSN) ; Alemzadeh, I ; Sharif University of Technology
Taylor and Francis Ltd
2017
Abstract
In this study, anti-leukemic enzyme L-asparaginase (E.C.3.5.1.1) from Escherichia coli ATCC 11303 was modified by the microencapsulation technique onto calcium alginate beads. Using response surface methodology (RSM), a three-level full factorial design, the values of concentration of sodium alginate, concentration of calcium chloride, and enzyme loading were investigated to obtain the highest residual L-asparaginase (L-ASNase) activity % (immobilized enzyme activity/free enzyme activity). The effects of the studied factors on immobilization were evaluated The predicted values by the model were close to the experimental values, indicating suitability of the model. The results presented that...