• BMB Reports
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• v.39 no.6
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• pp.671-676
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• 2006

The holoenzyme of protein phosphatase (PP) from tulip petals was purified by using hydrophobic interaction, anion exchange and microcystin affinity chromatography to analyze activity towards p-nitrophenyl phosphate (p-NPP). The catalytic subunit of PP was released from its endogenous regulatory subunits by ethanol precipitation and further purified. Both preparations were characterized by immunological and biochemical approaches to be PP2A. On SDS-PAGE, the final purified holoenzyme preparation showed three protein bands estimated at 38, 65, and 75 kDa while the free catalytic subunit preparation showed only the 38 kDa protein. In both preparations, the 38 kDa protein was identified immunologically as the catalytic subunit of PP2A by using a monoclonal antibody against the PP2A catalytic subunit. The final 623- and 748-fold purified holoenzyme and the free catalytic preparations, respectively, exhibited high sensitivity to inhibition by 1 nM okadaic acid when activity was measured with p-NPP. The holoenzyme displayed higher stimulation in the presence of ammonium sulfate than the free catalytic subunit did by protamine, thereby suggesting different enzymatic behaviors.

• Journal of Life Science
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• v.11 no.5
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• pp.415-422
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• 2001

Many secreted proteins have disulfide bonds that are important for their structure and function. Protein disulfide isomerase (PDI, EC 5.3.1.4.), an enzyme that catalyzes the formation and rearrangement of thiol/disulfide exchange reactions, is a resident of the endoplasmic reticulum (ER). The subcellular localization and its function as catalyst of disulfide bond formation in the biosynthesis of secretory and cell membrane proteins suggest that PDI plays a key role in the secretory pathway. We have isolated a cDNA encoding protein disulfide isomerase from Bombyx mori(bPDI). It has been characterized under ER stress conditions (dominantly induced by calcium ionophore A23187, tunicamycin and DTT), which is known to cause an accumulation of unfolded proteins in the ER. Furthermore, It has also been examined for tissue distribution(pronounced at the fat body), hormonal regulation (juvenile hormone, insulin and juvenile +transferrin; however, it is not effected by transferrin alone), and the effect of exogenous bacteria (peak at 16 h after infection) on the bPDI mRNA expression. The results suggest that bPDI is a member of the ER stress protein group, and it may play an important role in exogenous bacterial infection in fat body, and that homones regulate its expression.

• The Korean Journal of Food & Health Convergence
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• v.4 no.4
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• pp.18-25
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• 2018

Proteins play a key role in many functions such as metabolic activity, differentiation, as cargos and cell fate regulators. It is necessary to know about the markers involved in male fertility in order to develop remedies for the treatment of male infertility. But, the role of the proteins is not limited to particular function in the biological systems. Some of the proteins act as ion channels such as catsper and proteins like Nanos acts as a translational repressor in germ cells and expressed in prenatal period whose role in male fertility is uncertain. Rbm5 is a pre mRNA splicing factor necessary for sperm differentiation whose loss of function results deficit in sperm production. DEFB114 is a beta defensin family protein necessary for sperm motility in LPS challenged mice where as TEX 101 is a plasma membrane specific germ cell protein whose function is not clearly known u to now. Gpr56 is another adhesion protein whose null mutation leads to arrest of production of pups in rats. Amyloid precursor protein role in Alzheimer's disease is already known but it plays an important role in male fertility also but its function is uncertain and has to be considered while targeting APP during the treatment of Alzheimer's disease. The study on amyloid precursor protein in male fertility is a novel thing but requires further study in correlation to alzheimer's disease.

• Proceedings of the Korean Biophysical Society Conference
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• 2003.06a
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• pp.65-65
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• 2003

After many genome projects, algorithms and software to process explosively growing biological information have been developed. To process huge amount of biological information, high performance computing equipments are essential. If we use the remote resources such as computing power, storages etc., through a Grid to share the resources in the Internet environment, we will be able to obtain great efficiency to process data at a low cost. Here we present the performance improvement of the protein secondary structure prediction (PSIPred) by using the Grid platform, distributing protein sequence data on the Grid where each computer node analyzes its own part of protein sequence data to speed up the structure prediction. On the Grid, genome scale secondary structure prediction for Mycoplasma genitalium, Escherichia coli, Helicobacter pylori, Saccharomyces cerevisiae and Caenorhabditis slogans were performed and analyzed by a statistical way to show the protein structural deviation and comparison between the genomes. Experimental results show that the Grid is a viable platform to speed up the protein structure prediction and from the predicted structures.

• Journal of Periodontal and Implant Science
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• v.36 no.1
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• pp.155-165
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• 2006

The results of this study confirm that the availability of hemin influences the expression of selected membrane proteins of Porphyromonas gingivalis, Prevotella intermedia, and Prevotella nigrescens. A 30 kDa (heated 24 kDa) hemin-binding protein whose expression is hemin regulated was identified and purified in P. gingivalis. A strong hemin-binding function was found by LDS-PAGE and TMBZ staining when P. gingivalis cells were grown under hemin-limited conditions. A 50 kDa cell envelope associated protein, whose expression is hemin regulated, is considered to be a putative hemin binding protein from P. intermedia and P. nigrescens, respectively. N-terminal amino acid sequence analysis of CNBr-digested 24 kDa hemin binding protein from P. gingivalis revealed that this protein belongs to a new, so far undescribed hemin-binding class of proteins. N-terminal amino acid sequence of a 50 kDa putative hemin binding protein from P. intermedia was identical with Enolase from Streptococcus intermedia. Work is in progress to further characterize the molecular structure of these proteins.

• Journal of Microbiology and Biotechnology
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• v.32 no.9
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• pp.1209-1216
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• 2022

To better understand the effects of PEGylation and biotinylation on the delivery efficiency of proteins, the cationic protein lysozyme (LZ) and anionic protein bovine serum albumin (BSA) were chemically conjugated with poly(ethylene glycol) (PEG) and biotin-PEG to primary amine groups of proteins using N-hydroxysuccinimide reactions. Four types of protein conjugates were successfully prepared: PEGylated LZ (PEG-LZ), PEGylated BSA (PEG-BSA), biotin-PEG-conjugated LZ (Bio-PEG-LZ), and biotin-PEG-conjugated BSA (Bio-PEG-BSA). PEG-LZ and Bio-PEG-LZ exhibited a lower intracellular uptake than that of LZ in A549 human lung cancer cells (in a two-dimensional culture). However, Bio-PEG-BSA showed significantly improved intracellular delivery as compared to that of PEG-BSA and BSA, probably because of favorable interactions with cells via biotin receptors. For A549/fibroblast coculture spheroids, PEG-LZ and PEG-BSA exhibited significantly decreased tissue penetration as compared with that of unmodified proteins. However, Bio-PEG-BSA showed tissue penetration comparable to that of unmodified BSA. In addition, citraconlyated LZ (Cit-LZ) showed reduced spheroid penetration as compared to that of LZ, probably owing to a decrease in protein charge. Taken together, chemical conjugation of targeting ligands-PEG to anionic proteins could be a promising strategy to improve intracellular delivery and in vivo activity, whereas modifications of cationic proteins should be more delicately designed.

• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.10
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• pp.1676-1684
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• 2004

Gel properties of recovered protein from mackerel, frozen blackspotted croaker, chicken breast and pork leg using acidic and alkaline processing were evaluated. Myofibrillar protein from mackerel by acidic processing did not form a heat-induced gel. However, the recovered protein including sarcoplasmic protein formed heatinduced gel. Breaking force of gel from mackerel processed at pH 10.5 was the lowest. A deformation value of frozen blackspotted croaker was the highest, followed by chicken breast, pork leg and mackerel. Whiteness of frozen blackspotted croaker was the highest among heat-induced gel. Breaking force, deformation and whiteness were decreased by addition of recovered protein from mackerel, but price was increased. A breaking force and whiteness of heat-induced gel added recovered protein from chicken breast were increased, and the price was greatly decreased. When the constraint of breaking force, deformation and price of raw material were set up above 110 g, 4.5 mm and below 2,000 won/kg. A optimum formulation for blending protein was 36∼50% for frozen blackspotted croaker, 34∼40% for chicken breast, 14∼25% for pork leg. The heat-induced gel of recovered protein from frozen blackspotted croaker showed compact structure compared to that of recovered protein from mackerel. A formulation of chicken breast and pork leg based on blackspotted croaker can be used in surimi based seafood products having various texture.

• Biomedical Science Letters
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• v.6 no.4
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• pp.237-244
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• 2000

It has been reported that plasma membrane activity of the spermatozoa may be susceptible to be influenced by extracellular osmolality and such membranous changes involve infracellular molecular changes, special regard to the structure of membranous lipids, and the accompanying ion-channel of which are closely related with their fluidity of $Ca^{2+}$ and HCO$^{-}_{3}$. It is of common recognition that a certain kind of sterol acceptor player an important to induce lipid fluctuation of the sperm plasma membrane which have been influenced by BSA administration and came in effect to outflow of cholesterol from the spermatozoa and resulted in changes of ionic fluidity to facilitate adenylyl cyclase, and to induce protein tyrosine phosphorylation by increase of cAMP and activation of PKA. Thus it seems likely that an augmentation of the acrosomal reaction is closely related with protein tyrosine phosphorylation. The following experimental results were obtained in the present study; Under the high osmolality conditions, the spermatozoa motility declined significantly and the structural change of the plasma membrane diminished to confirm that the response degrees to the osmolality depended upon the water transfer volume through the plasma membrane and the changes of cellular volume. Those experimental results suggest that a physiological parameter such as low temperature condition played an important role for presentation of spermatozoa and that inducement of spermatozoa activation for reinforcement of protein tyrosine phosphorylation. On the other hand, it seemed likely that the BSA administration as one of sterol accepters might represent a key role also under the high osmolality condition and their result also suggests that osmolality change, special regard to high osmolality condition may play an important role also in the processes of signal transmission.

• Journal of Life Science
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• v.9 no.1
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• pp.35-43
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• 1999

Leaf protein (LP) was prepared by centrifugation the green juice from Italian ryegrass (Lolium multiflorum Lam.) at acid precipitation. LP was compared with casein and soybean protein isolate for their concentration of serum lipids and free amino acids in Wistar male rats for 2 weeks. Each protein source was incoporated into cholesterol free, low-fat diet to provide a protein level of 20%. A comparison of serum amino acids in leaf protein-fed vs. casein-fed rats showed that, glycine was the only amino acid having a higher concentration whereas concentration of other amino acids were lower in the leaf protein-fed rats compared with the casein-fed rats. Further alanine was significantly lower in the leaf protein-fed rats compared with the casein-fed rats, and the protein-induced differences in glycine and alanine concentration of unfed rats were reproducible. Concentration of several amino acids, rarticularly valine, leucine and tyrosine, also changed when serum cholesterol concentrations varied, but these effects could not be explained by our experiments. The results suggest that a change in serum concentration of glycine and alanine of unfed rats may be related to the change in serum cholesterol concentration. These data also suggest appear to function in a similar way to soybean protein in their hypocholesterolemic action.

• Proceedings of the SCSK Conference
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• 2003.09a
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• pp.142-160
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• 2003

Most consumers have noted hair damage following coloring treatments. Proper evaluation of hair bleaching products must be performed using quantitative assessments of hair damage, though they are difficult, because of the slight fluctuations in hair composition. In the present study, we utilized a sensitive evaluation method for hair damage and found that the amount of soluble protein fraction extracted from hair under a reducing condition, termed labile protein, dramatically increased after bleaching.(omitted)