Saccharomyces cerevisiae KNU5377의 과산화 수소에 대한 항산화 시스템의 연구
Analysis of antioxidant defense system against hydrogen peroxide in Saccharomyces cerevisiae KNU5377
항산화시스템 Saccharomyces cerevisiae KNU5377 과산화수소;
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Oxygen is known to be essential or dangerous for aerobic life. During the reduction of molecular oxygen to water via the acceptance of electron, reactive oxygen species (ROS) such as the superoxide radical (O_(2)^(-)), hydrogen peroxide (H_(2)O_(2)) and the hydroxyl radical (HO^(-)) are generated. These reactive oxygen species attack almost all cell components such as DNA, protein and lipid, and others ROS are known to be causative of degenerative diseases such as cancer, Alzheimer's disease, respiratory distress syndrome, muscular dystrophy and aging. Against ROS, cells possess both enzymatic and non-enzymatic defence systems to protect their cellular constituents and maintain cellular redox state. None-enzymatic defence systems act as radical scavengers. Enzymatic defence systems are capable of removing oxygen radicals and their by-product and repairing the damage caused by oxidative stress. Using S. cerevisiae KNU5377, we have examined to induce adaptation to hydrogen peroxide stress and to assay role of a set of well-known antioxidant enzymes. We compared non-pretreatment (treated 20 mM H_(2)O_(2)) with pre-treated cells (treated 1mM H_(2)O_(2)for 1 hr before being treated 20 mM H_(2)O_(2)). None-pretreatment increased lipid peroxidation and protein carboxylation much more than pre-treated cells. Using the western blot and RT-PCR, we observed that cells with pre-treatment increased antioxidant defense system much more than cells without pre-treatment. The mRNA and protein expression of catalase A and glutathione peroxidase Ⅱ were higher than others. The expression level of heat shock proteins was also increased with the time dependent. When microarray analysis was observed, expression of thioredoxin system genes were higher than that of glutathione system gene. When Up and down-regulated proteins level by 2-D gel electrophoresis image analysis was observed, total protein of over one fold expressed 20.7% protein spot under 20 mM H_(2)O_(2) stress or total protein of below one fold expressed 39.8% protein spot under 20 mM H_(2)O_(2) stress. After exposure to H_(2)O_(2) stress, S. cerevisiae KNU5377 showed the adaptive response of their own cells for the acquisition of stress tolerance. In the shocked cells of this strain, heat shock protein, catalase A, glutathione reductase Ⅱ, and thioredoxin antioxidant system played more important roles in the adaptive response to H_(2)O_(2) stress.