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Characterisation of recombinant mouse glutamate carboxypeptidase III
Janoušková, Karolína ; Konvalinka, Jan (advisor) ; Obšil, Tomáš (referee)
Glutamate carboxypeptidase II (GCPII, PSMA, NAALADase) is transmembrane metalopeptidase and due to cleavage of substrates β-citryl-L-glutamate (BCG), N-acetyl-L-aspartyl-L-glutamate (NAAG) and polyglutamylated folates (Pte-Glun) is being studied as potential therapeutic target. Enzymes, which could compensate for enzyme activity and functions of GCPII, are thus relevant targets of enzymology as well. One of GCPII's homologs with similar enzyme activity is mouse glutamate carboxypeptidase III (GCPIII, NAALADase II). Enzymatic cleavage has not been determined using recombinant mouse GCPIII yet. It is important to kinetically characterize mouse GCPIII so that we can compare enzyme activity with human ortolog. Then we can find out whether mouse model is comparable with human. Recombinant mouse GCPIII was kinetically characterized. Kinetic parameters (KM, kcat) for recombinant mouse GCPIII were measured for substrates NAAG and BCG using radioactive assay. Experiments with the substrate Pte-Glu2 were analyzed using HPLC method. Although human GCPIII is more effective than mouse ortolog at clearage of NAAG, both enzymes are comparable during hydrolysis of BCG. Those results can contribute to better understanding of the role of GCPIII in the most commonly used animal model.
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Preparation of glutamate carboxypeptidase III using mammalian expression system
Šimonová, Lenka ; Konvalinka, Jan (advisor) ; Obšil, Tomáš (referee)
The role of glutamate carboxypeptidase II in mammalian organism is already known quite well but only little is known about its homologue glutamate carboxypeptidase III. For structural and functional characterization of any protein, a large amount of protein is required. Protein could be obtained by expression in tissue culture. Properties of the protein may be affected by post translational modifications, where different organisms create different modifications. Therefore, we set to develop a system for recombinant expression of GCPIII in mammalian cells. First the mammalian expression system HEK 293-6E was introduced as a substitute for the current insect expression system. The advantage of this mammalian expression system is its option of transient transfection and that it is easy to cultivate cells under suspension conditions. Further, transfection conditions for this system were optimized by green fluorescent protein expression, for easy detection by flow cytometry. DNA encoding the extracellular part of mouse GCPIII (mEXSTII) was cloned into five expression plasmids with His or Fc tags attached to N- or C-termini. Cells were transfected with prepared plasmids. The presence of mEXSTII in media was tested using Western blot and subsequently the activity of GCPIII was tested by cleaving its...
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Characterisation of recombinant mouse glutamate carboxypeptidase III
Janoušková, Karolína ; Konvalinka, Jan (advisor) ; Obšil, Tomáš (referee)
Glutamate carboxypeptidase II (GCPII, PSMA, NAALADase) is transmembrane metalopeptidase and due to cleavage of substrates β-citryl-L-glutamate (BCG), N-acetyl-L-aspartyl-L-glutamate (NAAG) and polyglutamylated folates (Pte-Glun) is being studied as potential therapeutic target. Enzymes, which could compensate for enzyme activity and functions of GCPII, are thus relevant targets of enzymology as well. One of GCPII's homologs with similar enzyme activity is mouse glutamate carboxypeptidase III (GCPIII, NAALADase II). Enzymatic cleavage has not been determined using recombinant mouse GCPIII yet. It is important to kinetically characterize mouse GCPIII so that we can compare enzyme activity with human ortolog. Then we can find out whether mouse model is comparable with human. Recombinant mouse GCPIII was kinetically characterized. Kinetic parameters (KM, kcat) for recombinant mouse GCPIII were measured for substrates NAAG and BCG using radioactive assay. Experiments with the substrate Pte-Glu2 were analyzed using HPLC method. Although human GCPIII is more effective than mouse ortolog at clearage of NAAG, both enzymes are comparable during hydrolysis of BCG. Those results can contribute to better understanding of the role of GCPIII in the most commonly used animal model.
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Preparation of glutamate carboxypeptidase III using mammalian expression system
Šimonová, Lenka ; Konvalinka, Jan (advisor) ; Obšil, Tomáš (referee)
The role of glutamate carboxypeptidase II in mammalian organism is already known quite well but only little is known about its homologue glutamate carboxypeptidase III. For structural and functional characterization of any protein, a large amount of protein is required. Protein could be obtained by expression in tissue culture. Properties of the protein may be affected by post translational modifications, where different organisms create different modifications. Therefore, we set to develop a system for recombinant expression of GCPIII in mammalian cells. First the mammalian expression system HEK 293-6E was introduced as a substitute for the current insect expression system. The advantage of this mammalian expression system is its option of transient transfection and that it is easy to cultivate cells under suspension conditions. Further, transfection conditions for this system were optimized by green fluorescent protein expression, for easy detection by flow cytometry. DNA encoding the extracellular part of mouse GCPIII (mEXSTII) was cloned into five expression plasmids with His or Fc tags attached to N- or C-termini. Cells were transfected with prepared plasmids. The presence of mEXSTII in media was tested using Western blot and subsequently the activity of GCPIII was tested by cleaving its...
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