Do Youn Lee

Development of an effective sample preparation method for the proteome analysis of body fluids using 2-D gel electrophoresis

A sample preparation is still the most critical step in two-dimensional electrophoresis (2-DE) and should be optimized for each type of sample. In this study, a protein extraction method from body fluids was developed using a combined centrifugal filter device and a sample treating buffer. When plasma, amniotic fluid, urine, and tear were tested with this method, the recovery of protein reached almost 90% and high-quality separation of 2-DE gel was obtained.

Concentration and purification of soluble pectin from mandarin peels using crossflow microfiltration system

A crossflow microfiltration process was developed to concentrate and purify soluble pectin extracted from the mature citrus peel. The extracted pectin solution was concentrated with the crossflow microfiltration using a 0.2 μm regenerated cellulose membrane. As a result of crossflow microfiltration, the galacturonic acid content of pectin increased from 68.0 to 72.2% while the recovery yield of pectin decreased from 10.5 to 9.9%. In addition, the volume of ethanol used for the recovery of pectin could be reduced to 25%. To purify pectin further, the concentrated pectin extracts was washed using the fed-batch type diafiltration system. By diafiltration, the galacturonic acid content of pectin increased from 72.2 to 75.6%. The yield of pectin, however, decreased from 9.9 to 9.4% at six volumes of diafiltration. The diafiltration process was also effective to remove flavonoids, polyphenols and carotenoids, which were impurities in pectin products. Therefore, the crossflow microfiltration system could be efficiently used for concentration and purification of pectin.

Analysis of Differentially Regulated Proteins in TM4 Cells Treated with Bisphenol A

BPA, bisphenol A, a monomer of epoxy resins and polycarbonate plastic, is used in many consumer products including the plastic linings of cans for food and babies’ bottles. BPA has been reported to cause reproductive toxicity and affects cells in rats and mice at high doses. In this study, the effect of BPA on protein expression in TM4 cells (a mouse Sertoli cell line) known to play an essential role in Spermatogenesis was investigated by two-dimensional electrophoresis (2-DE). After 16 h exposure to 50, 100, 150, 200, and 250 μM of BPA, the viability of TM4 cells decreased to about 90, 85, 78, 55, and 30% of control respectively. Approximately 800 protein spots in TM4 cells were analyzed by 2-DE with pH 4–7 linear immobilized pH gradient (IPG) Dry Strip, and 11 proteins which showed significantly different expression levels were identified by matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS). Among these, HSP 27 and placental calcium binding protein may be proteins differentially expressed by BPA exposure.