korea inu

Biochemistry Laboratory

 Name   Choi, Eun-Mi
 Education   Ph.D., Iowa State University, USA, 1989
 Office   No. 05-451 / TEL : +82-32-835-8233 / E-mail : eunmi@incheon.ac.kr
 Lab   Biochemistry laboratory / No. 05-408 / TEL : 032-835-4559

 Research Fields

• main research field - Biochemistry
• detail research field - Oxidative stress, Antioxidant metabolism, Protein chemistry

 Research Interests

Our main research interests are the effect of oxidative stress and the antioxidant metabolism in cells. Aerobic cells gain energy effectively by using oxygen as the ultimate electron acceptor. However, even under normal metabolic conditions, reactive oxygen species (ROS) can be generated as byproducts due to incomplete reduction of the oxygen by electrons leaked from mitochondrial electron transport chain.

Extracellular agents such as UV, ionizing radiation, environmental toxins, and drugs can amplify the ROS generation. The ROS are very reactive to cause oxidative damage to cell materials such as proteins, nucleic acids and membrane lipids. The ROS-induced oxidative damages are known to be main causes for the aging and the development and progression of diseases such as cancer, rheumatoid arthritis, and Alzheimer.

In order to cope with the oxidative damage, the aerobic cells are endowed with a battery of antioxidative defense mechanisms including endogeneous antioxidant molecules and enzymes. Under normal conditions, a balance between oxidants and antioxidants is maintained. When the ROS generation overwhelms the antioxidant capacity, a disturbance in the oxidant-antioxidant balance causes the oxidative stress in cells leading to the cell damage.

The ROS, on the other hand, are also needed to play essential roles. ROS can be used to fight against athogens. In addition, many metabolic events such as transport, transcription and translation are known to be under redox regulation that is affected by homeostatic control of oxidant/antioxidant ratio.

One of the research focuses in our laboratory is the glutathione metabolism under oxidative stress. The glutathione is an antioxidant peptide that is composed of three amino acids including a cysteine. The glutathione removes ROS either by direct interaction or by enzymatic reaction such as glutathione peroxidase.

In addition, glutathione can protect proteins from irreversible oxidation by forming mixed-disulfide with protein thiols (S-thiolation) under oxidative stress. We have studied the roles of ROS and antioxidant system in the diseases such as diabetes and in the damage caused by extracellular agents such as ionizing radiation. Currently, we are investigating the antioxidant system in marine algae to search for antioxidant molecules that protect skin cells from UV.

 Selected Publications

"Antioxidant activities in the lung of murine Hermansky-Pudlak Syndrome (HPS) model: Effect of ionizing radiation" Shin HS, Yang WJ, Choi EM. J. Environ. Toxicol. 2007, 22(1), 9-17.

"Susceptibility of cigarette smoke condensate-exposed human bronchial epithelial cells to hypoxia-reoxygenation" Lee IJ, Choi EM. J. Environ. Toxicol. 2009, 24(1), 53-61.

"Prevention of alloxan-induced diabetes by Se-methylselenocysteine pretreatment in rats: The effect on antioxidant system in pancreas" Nam TI, Park JJ, Choi EM . J. Food Sci. Nutr. 2009, 14(2), 95-101.

"High superoxide dismutase and low glutathione peroxidase activities in red blood cells predict susceptibility of lung cancer patients to radiation pneumonitis" Choi EM, Ramnath N, Yang GY, Ahn JY, Park Y, Lee TY, Shin HS, Yu J, Ip C, Park YM. Free Radic Biol Med. 2007, 42(2), 280-287.

"Prx1 suppresses radiation-induced c-Jun NH2-terminal kinase signaling in lung cancer cells through interaction with the glutathione S-transferase Pi/c-Jun NH2-terminal kinase complex" Kim YJ, Lee WS, Ip C, Chae HJ, Choi EM, Park YM. Cancer Res. 2006, 66(14), 7136-7142.

"Hypoxia increases androgen receptor activity in prostate cancer cells" Park SY, Kim YJ, Gao AC, Mohler JL, Onate SA, Hidalgo AA, Ip C, Choi EM, Yoon SY, Park YM. Cancer Res. 2006, 66(10), 5121-5129.

"A display thiol-proteomics approach to characterize global redox modification of proteins by selenium: Implication for the anticancer action of selenium" Choi EM, Choi KS, Park SY, Zhang H, Ip C, Park YM. Cancer Genomics and Proteomics, 2005, 2(1), 25-36.

"Effect of ionizing radiation on rat tissue: proteomic and biochemical analysis" Park EC, Yoon JB, Seong JS, Choi KS, Kong ES, Kim YJ, Park YM, Choi EM. Prep Biochem Biotechnol. 2006, 36(1), 19-35.