Experimental Course of Chemistry of Molecular Biocatalysts1
| Numbering Code | G-AGR03 5CC39 EB79 | Year/Term | 2022 ・ Year-round |
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| Number of Credits | 6 | Course Type | Experiment |
| Target Year | Target Student | ||
| Language | Japanese | Day/Period | |
| Instructor name |
YAMAGUCHI SHINJIRO (Institute for Chemical Research Professor) mashiguchi kiyoshi (Graduate School of Agriculture Assistant Professor) |
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| Outline and Purpose of the Course | Life consists of an integrated network of chemical reactions mediated by enzymes. The objectives of this experimental course are to learn through experiments 1) how to develop the novel and small organic molecules that specifically inhibit or stimulate the physiologically relevant enzymes or proteins, 2) how to synthesize the target molecules, 3) how to evaluate the in vitro and in vivo activities of the synthesized compounds, 4) how to probe the physiological functions of the respective enzymes or proteins by using the compounds as a chemical probe and 5) how to elaborate the compounds to generate innovative bioactive substance that could be used for novel medicinal, agricultural chemicals and cosmetic ingredients. In this experimental course, students can learn the basics of practical (bio)organic chemistry by molecular design of enzyme inhibitors or activators, organic synthesis and analytical methods. Students can also learn the basics of biochemical techniques such as handling of genes and proteins, enzyme kinetics and bioassays. | ||
| Course Goals | Students have an ability to understand the molecular design and synthesis of the small molecules that modify physiological relevant enzymes' activity. The students can understand how the molecules modify the respective enzymes activity or the mode of action of the molecules. Students have an ability of searching for previous research on their topics. | ||
| Schedule and Contents |
We are particularly interested in augmenting cellular defense against oxidative stress and/or toxic xenobiotics assault by using small organic molecules that modify cellular redox potential to induce anti-oxidative responses of cells. This can be done by specific inhibitors or activators of the enzymes that mediate the metabolism of glutathione, a key tripeptide in cellular anti-oxidative defense system. γ-Glutamyl transpeptidase (GGT) is a highly promising target enzyme due to its critical role in the extracellular hydrolysis of glutathione to supply cells with Cys, the rate-limiting substrate for the biosynthesis of glutathione. The specific inhibitors of GGT can therefore reduce intracellular glutathione level, thereby inducing a slight oxidative stress that in turn could induce the cellular antioxidative responses. Conversely, the enhanced GGT activity is responsible for augmenting intracellular glutathione level, which is frequently observed in drug resistant cancer cells with increased malignant phenotypes. Therefore the specific inhibitors and/or the activators of human GGT are an interesting topic. The students assigned to this project are to develop novel mechanism-based GGT inhibitors that could covalently be bound to the enzyme active site to inactivate GGT. The activators of human GGT are also targeted to unravel the detailed molecular mechanisms of human GGT in the hydrolysis of glutathione. The molecular design of the inhibitors and/or activators of human GGT could then be utilized to develop specific inhibitors and/or activators of other GGT family enzymes. The covalent-type inhibitors could also be elaborated to develop a novel tagging device directed toward the GGT of cancer cells to label, for example, with a fluorescent marker or a specific antigen that could induce immune response. Another promising target in this line is the transporter of cystine. The availability of Cys is essential for glutathione biosynthesis, and the uptake of cystine accounts significantly for the total Cys availability. Cancer cells such as glioma and lymphoma express high levels of cystine transporter to cope with oxidative stress and assault by anticancer drugs. Therefore the inhibitors of the cystine transporter are an interesting topic for controlling the cellular oxidative stress and developing novel anti-cancer drugs. The students assigned to this project are to develop specific inhibitors of the transporter. This can be done by molecular design of cystine analogues that could compete with cystine or get stuck in the transporter to block the cystine transport. The transport through cell membranes is another remarkable facet of biocatalysts (transport catalysis). The inhibitors of cystine transporter, if successful, would present a leading principle for developing specific inhibitors of other physiologically relevant transporters. Other research topics include the structure-activity relationships of plant secondary metabolites such as eugenol (alkenylbenzenes) to unravel the hidden chemistry in the delicate balance between their toxic and beneficial effects for human health. This topics is closely related to the above mentioned anti-stress responses, because glutathione and its metabolism is involved in the detoxification process. The students are to learn how to rationalize, on a chemical basis, the effects of plant origin natural products and their derivatives. |
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| Evaluation Methods and Policy |
Daily achievements in laboratory works (evaluated by progress report and short presentation in a weekly meeting) Oral presentation of the results at a conference (at least once in two years) The completion of a master thesis at the end of the course. Refer to current year's 'Guide to Degree Programs' for attainment levels of evaluation. |
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| Course Requirements |
Basics of organic chemistry, biochemistry and enzyme chemistry English literacy in reading, writing and speaking Basics of Japanese literacy in daily life |
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| Study outside of Class (preparation and review) | Students have to search for the relevant articles on previous research on the topics. | ||
