• Preventive Nutrition and Food Science
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• v.10 no.1
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• pp.88-91
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• 2005

To improve the physical properties of protein films, various plasticizers and cross-linking agents were used in the preparation of the films. For zein film, 3% polypropylene glycol with 3% glycerol was the best plasticizer, while 2.5% glycerol was the most suitable for soy protein isolate (SPI) film in terms of tensile strength (TS), % elongation, and water vapor permeability (WVP). Formaldehyde, glutaraldehyde, glyoxal, and cinnamaldehyde as cross-linking agents of protein films were used to further improve the physical properties of the films. All aldehydes used as cross-linking agent in this study improved TS of zein and SPI films. In particular, cinnamaldehyde was the best cross-linking agent due to its safety in foods. These results suggest that appropriate use of plasticizer and cross-linking agent like cinnamaldehyde should improve the physical properties of protein films for use in food packaging.

• Journal of Applied Biological Chemistry
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• v.42 no.2
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• pp.81-84
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• 1999

Blood glue was prepared to reutilize porcine blood. Plasma proteins after lyophilization were treated by addition of wood flour, sodium hydroxide, sodium silicate, and hydrated lime to make blood glue with a suitable adhesivity. Characteristics of the prepared blood glue was monitored by measuring the viscosity with time, and the relationship between degree of hydrolysis of plasma proteins by addition of various amounts of sodium hydroxide and adhesivity was studied. To prevent the emission of formaldehyde during manufacturing of plywood by blood glue, the cross-linking reaction of plasma protein with formaldehyde was also examined. Fourier transform infrared, circular dichroism, and fluorescence spectroscopy study showed that blood plasma proteins react with formaldehyde, resulting in removal of formaldehyde by cross-linking reaction.

• Journal of Photoscience
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• v.9 no.2
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• pp.382-384
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• 2002

When illuminated with strong visible light, the reaction center Dl protein of photo system II is photodamage and degraded. Reactive oxygen species and endogenous cationic radicals generated by photochemical reactions are the cause of the damage to the Dl protein. Recently we found that the photodamaged Dl protein cross-links with the surrounding polypeptides such as D2 and CP43 in photosystem II. As the cross-linking reaction is dependent on the presence of oxygen, reactive oxygen species are suggested to be involved. Among the reactive oxygen species examined, ？ OH was most effective in the formation of the cross-linked products. These results indicate that the cross-linking is mostly due to ？ OH generated at photosystem II. The cross-linking site of the Dl protein is not known. As several tyrosine residues exist at the D­E loop of the Dl protein, there is a possibility that di-Tyr is formed between the D­E loop of the Dl protein and surrounding polypeptides during the strong illumination. Therefore, we examined the formation of di-Tyr using the monoclonal antibody against di-Tyr under excess illumination of the photosystem II membranes. The results obtained here suggest that no di-Tyr is formed during the excess illumination of photosystem II.

• Korean Journal of Food Science and Technology
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• v.30 no.2
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• pp.372-378
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• 1998

Two types of formaldehyde-treated soy protein isolate (SPI) films, formaldehyde-incorporated and formaldehyde-adsorbed films, and control SPI films were prepared. Cross-linking effect of formaldehyde on selected film properties such as color, tensile strength (TS), elongation at break (E), water vapor permeability (WVP), and water solubility (WS) were determined. Physical properties of formaldehyde-incorporated films were not geneally different from those of control films, while almost all of those among formaldehyde-adsorbed films were significantly different. Through cross-linking development within formaldehyde-adsorbed films, WS decreased significantly (P<0.05) from 26.1% to 16.6%, and TS increased two times while E decreased two times compared with control films. This was caused by insolubilization and hardening of protein by cross-linking most likely attributed to the significant changes in properties of protein films reacted with formaldehyde.

• Animal cells and systems
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• v.8 no.2
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• pp.125-133
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• 2004

We have extended our previous work that cross-linking CD4 molecules using specific MAb induced antigen nonspecific, MHC unrestricted killing of virally infected target cells by CD$4^+$We have extended our previous work that cross-linking CD$4^+$ molecules using specific MAb induced antigen nonspecific, MHC unrestricted killing of virally infected target cells by CD$4^+$ T cells. The killing activity of antibody activated CD$4^+$T cells was completely blocked by herbimycin A, a protein tyrosine kinase (PTK) inhibitor, but not by bisindolylamaleimide, a protein kinase C (PKC) inhibitor. Herbimycin A treated human or bovine peripheral blood CD$4^+$T cells lacked PTK activity and failed to kill virally infected target cells even after cross-linking of CD4 molecules. The CD$4^+$cross-linking failed to induce effector cell proliferation or the transcription of TNF${\beta}$ Upregulation of TNF${\beta}$ was induced by incubating the antibody activated effector cells with BHV-1 infected D17 target cells for 10 h. Anti-TNF${\beta}$ antibody partially abolished (13-44%) the direct effector cell-mediated antiviral cytotoxicity. However, this antibody neutralized 70 to 100% of antiviral activity of effector and target cell culture supernatants against BHV-1 infected D17 cells. The inhibition level of the antiviral activity by the antibody was dependent on the effector and target cell ratio. These results support the hypothesis that increased p$56^ICK enzyme activity in effector cells transduces a signal critical for effector cell recognition of viral glycoproteins expressed on the target cells. Following target cell recognition, lytic cytokines known to participate in target cell killing were produced. A better understanding of the killing activity displayed by CD$4^+$T lymphocytes following surface receptor cross-linking will provide insight into the mechanisms of cytotoxic activity directed toward virally-infected cells.T cells. The killing activity of antibody activated CD$4^+$T cells was completely blocked by herbimycin A, a protein tyrosine kinase (PTK) inhibitor, but not by bisindolylamaleimide, a protein kinase C (PKC) inhibitor. Herbimycin A treated human or bovine peripheral blood CD4T cells lacked PTK activity and failed to kill virally infected target cells even after cross-linking of CD4molecules. The CD4 cross-linking failed to induce effector cell proliferation or the transcription of TNF$\beta$. Upregulation of TNF$\beta$ was induced by incubating the antibody activated effector cells with BHV-1 infected D17 target cells for 10 h. Anti-TNF$\beta$ antibody partially abolished (13-44%) the direct effector cell-mediated antiviral cytotoxicity. However, this antibody neutralized 70 to 100% of antiviral activity of effector and target cell culture supernatants against BHV-1 infected D17 cells. The inhibition level of the antiviral activity by the antibody was dependent on the effector and target cell ratio. These results support the hypothesis that increased $56^ICK enzyme activity in effector cells transduces a signal critical for effector cell recognition of viral glycoproteins expressed on the target cells. Following target cell recognition, lytic cytokines known to participate in target cell killing were produced. A better understanding of the killing activity displayed by CD$4^+$T lymphocytes following surface receptor cross-linking will provide insight into the mechanisms of cytotoxic activity directed toward virally-infected cells.

• Journal of Photoscience
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• v.9 no.2
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• pp.55-58
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• 2002

The reaction center Dl protein of photosystem II is the target of photodamage by excess illumination. The Dl protein is damaged by reactive oxygen species generated by photochemical reactions and then degraded by specific proteolytic enzymes. We found that the Dl protein also cross-links with the surrounding polypeptides, such as D2 and CP43 in isolated thylakoids or photosystem II-enriched membranes from spinach under the illumination with strong visible light. The cross-linking was observed in spinach leaf discs as well when they were illuminated at higher temperature (40°C). It was also shown that the cross-linked products are digested efficiently by a protease(s) in the stroma. Thus the cross-linking/digestion processes of the Dl protein seem to comprise a new pathway in the turnover of the photodamaged Dl protein. It should be noted, however, that the cross-linked products of the Dl protein and CP43 induced by endogenous cationic radicals in the donor-side photoinhibition are resistant to proteolytic digestion. Accumulation of these cross-linked products in the thylakoids may lead to the decay of the function of chloroplasts and finally to the death of plant cells. Thus, we suggest that the quality control of photosystem II, especially removal of the cross-linked products of the Dl protein, is crucial for the survival of chloroplasts under the light stress.

• Korean Journal of Pharmacognosy
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• v.39 no.3
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• pp.249-254
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• 2008

An 80% EtOH extract and the solvent fractions of the seeds of Cornus officinalis were evaluated for their inhibitory activities against advanced glycation end products (AGEs) formation and AGEs-induced protein cross-linking in vitro. In vitro assay for AGEs-bovine serum albumin (BSA) formation showed that the 80% EtOH extract, n-hexane, EtOAc, n-BuOH and water fractions significantly inhibited AGEs formation with observed $IC_{50}$ values of 1.13, 17.64, 1.52, 1.24 and $3.27{\mu}g/ml$, respectively. In indirect AGEs-ELISA assay, the 800% EtOH extract, EtOAc and n-BuOH fractions exhibited more potent inhibitory activity on AGEs-BSA formation than aminoguanidine, a well know AGEs inhibitor. Furthermore, the 80% EtOH extract and all the solvent fractions inhibited concentration-dependently AGE-BSA cross-linking to collagen. The 80% EtOH extract, EtOAc, n-BuOH and water fractions also had a breaking activity against preformed AGE-BSA cross-linking concentration dependently. Thus these results suggest that the 80% EtOH extract and fractions of the seeds of C. officinalis could be an inhibitor as well as breaker of AGE-BSA cross-linking.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.19 no.2
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• pp.100-108
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• 1986

This study was carried out in order to investigate protein cross-linking in freeze-dried meat of flounder (Limanda herzensteini). Changes in solubility or extractability of proteins and electrophoretic patterns of the extracted proteins were determined to monitor the cross-linking during the storage of freeze-dried meat. Development of nonenzymatic browning and the loss of in vitro protein digestibilily were also measured to assess their influences on the changes of functional and nutritional properties of proteins. In addition, the effects of lysine added, and removal of fat and water extractives were also mentioned. The extractability of protein decreased upon storage time and temperature, and the loss of solubility of myosin was evident. In case of the samples stored at $5^{\circ}C$ for 150 days, the extractability of protein decreased $26.4\%$, while that of the samples stored at $20^{\circ}C$ for 60 days decreased about $39.7\%$. And it was noted that the loss of solubility of myosin was $68.3\%$ and $98.1%$ for the same storage conditions, respectively. It was noteworthy that the samples treated with $L-lysine{\cdot}HCl$ seemed to prevent more or less the loss of protein solubility, in that, even stored at $20^{\circ}C$ for 120 days, revealed only $57.03\%$ decrease. The nonenzymatic browning was proceeded with the increase of storage temperature, especially, in the samples treated with glucose. This suggests that the decrease in extractibility of myosin was accompanied by the extent of browning. But the browning was retarded in defatted samples. The in vitro apparent protein digestibility was also higher in the samples defatted or water extracted. It was suggested from these results that changes in properties of proteins in freeze dried fish meat were led by the protein cross-linking which was attributed to Maillard type of reactions and protein-lipid interactions.

• Composites Research
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• v.28 no.2
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• pp.40-45
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• 2015

The purpose of the present work was to preparation and study of full biodegradable Eco-friendly bio-composites by using renewable resources. In this study, wheat protein isolate (WPI) films were formed by cross linking with resorcinol through solution casting method for packaging applications. By varying the resorcinol content (10, 20, 30, 40, and 50 wt %), its effect on mechanical properties of the wheat protein isolate film was measured. The addition of 20% resorcinol led to an overall increase in the tensile strength from 5.2 to 18.6 MPa and modulus increase from 780 to 1132 MPa than WPI films. The % elongation was increased from 2.8 to 9.05 when compared to unmodified WPI film. A thermal phase transition of the prepared WPI was assessed by means of DSC. FTIR is evident that the characteristic WPI spectral IR bands shifted on cross-linking with resorcinol.

• Journal of Microbiology
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• v.35 no.4
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• pp.327-333
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• 1997

Although extensively characterized in human cells, no heterogeneous nuclear ribonucleoprotein(hnRNP) has been found in the fission yeast Schizosaccharomyces pombe which is amenable to genetic studies and more similar to mammals than Saccharomyces cerevisiae is in terms of RNA processing. As a first step to characterize hnRNPs from S. pombe, attempt was made to find human hnRNP A1 homologs from S. pombe. The RNA molecule (A1 winner) containing the consensus high-affinity hnRNP A1 binding site (UAGGGA/U) was synthesized in vitro and used in an ultraviolet(UV) light-induced protein-RNA cross-linking assay. A number of S, pombe proteins bound to the A1 winner RNA. An approximately 50-kDa protein(p50) cross-linked more efficiently to the A1 winner RNA than other proteins. The p50 protein did not cross-link to a nonspecific RNA, but rather to the A1-5’ SS RNA in which the consensus 5’ splice junction sites of S. pombe introns were abolished. This suggests that the p50 protein, however, did not bind to the single-stranded DNA to shich the human hnRNP A1 could bind and be eluted with 0.5M NaCl. Further analysis should reveal more features of this RNA-binding protein.