Pukyong National University

Thesis of an undergraduate student at PKNU, published in an international journal <Marine drugs>
A study on anti-freezing proteins using 'ice binding protein' in antarctica living organisms

The thesis by an undergraduate student at Pukyong National University (President Jang Young-soo) was published in <Marine drugs>, an international academic journal in the field of marine medicine, attracting the public's attention.

Lee Young-hoon, a 4th grade student in the Department of Chemistry at Pukyong National University, recently published the paper ‘Protection of Alcohol Dehydrogenase against Freeze-thaw Stress by Ice-Binding Proteins is Proportional to their Ice-Recrystallization Inhibition Property’ (advisory prof. Kim Hak-jun) in this journal as the first author.

<Marine Drugs> is an SCI-level international academic journal with a citation index (IF) of 4.073 issued by MDPI, a large Swiss publishing company.

In this paper, Lee Young-hoon drew attention by revealing the results of a study that lends Freeze-thaw Stress to enzymes using ice-binding proteins.

Ice binding proteins are proteins that are mainly present in antarctica living organisms. It is a protein that is resistant to freezing by preventing the formation of ice crystals. If this protein is used, it can provide freezing-thaw stress against various substances, so even if it is frozen and thawed several times, the properties of the substance can be preserved.

In this study, Lee Young-hoon repeatedly frozen and melted two ice-binding proteins with different resistance to recrystallization of the ice and alcohol dehydrogenase. Then he observed the structural change using the fluorescent material ANS.

As a result of the study, it was found that the ice-binding protein with high resistance to recrystallization of the ice has less structural change due to freezing-thawing, and the general protein ADH has a relatively large structural change.

In particular, the concentration of ice-binding protein that practically preserves the activity was also found. As a result of measuring the activity change of alcohol dehydrogenase by varying the concentration of alcohol dehydrogenase and ice-binding protein, it was found that there is a significant effect when ice-binding protein (LeIBP) with high resistance to ice recrystallization was used at a concentration of 500 µg/ml or more.

He said, "Through this study, I was able to find out the types and concentrations of ice-binding proteins that can preserve their activity as much as possible in the process of freezing and thawing proteins. I plan to continue my follow-up studies so that my findings can be applied to the cryopreservation method of a variety of other proteins such as drugs and food." <Pukyong today>