• Preventive Nutrition and Food Science
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• 제2권4호
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• pp.281-284
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• 1997

Heat-induced gelation is an important functional property of whey proteins. Preheating of calcium reduced whey was reported to increase gel strength. 5% whey-protein solutions were preheated at pH7 and at various temperatures(60~8$0^{\circ}C$) for 15 minutes. The amount of soluble aggregates and denaturation enthalpy of preheated whey proteins were measured. Preheating temperature was negatively correlated with denaturation enthalpy($R^2$=0.857, P=0.08) and positive with the amount of soluble aggregates($R^2$=0.921, P=0.002). Denaturation enthalpy was negatively correlated with gel strength($R^2$=0.93, P=0.002). Soluble aggregates and gel strength were positively correlated($R^2$=0.972, P=0.0003). The formation of three dimensional gel network requires controlled protein denaturation and aggregation. Since preheating leads to the partial denaturation of proteins and the formation of soluble aggregates, preheated whey proteins have a higher gel strength than non-preheated one.

• Preventive Nutrition and Food Science
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• 제11권1호
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• pp.73-77
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• 2006

Ground pork was irradiated with an electron beam (e-beam) at a dose of 0, 1.5, 3, 5 and 10 kGy and the changes in various functional and other associated properties of salt-soluble proteins extracted from the pork were evaluated. Irradiation did not affect turbidity and the disulfide content of pork salt-soluble protein, but the content of sulfhydryls and the hydrophobocity of salt-soluble protein increased. This indicates that protein degradation occurred when the pork was e-beam irradiated and that the sulfhydryls and hydrophobic moieties buried inside the proteins were exposed to the outside environment. However, these degraded protein molecules did not form large protein aggregates through disulfide bridges. The emulsifying capacity of the pork increased with irradiation, which could be the result from increased hydrophobicity of pork salt-soluble protein. Water holding capacity of pork was not affected bye-beam irradiation.

• Journal of Animal Science and Technology
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• 제62권4호
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• pp.533-542
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• 2020

The objective of this study was to observe the interactions between salt-soluble proteins extracted from beef and elephant foot yam (Amorphophallus campanulatus) flour in heat-induced gel matrix development. The effect of salt concentration; 0.5%, 1.0%, 1.5%, and 2.0% in weight/weight basis (w/w), during protein extraction on pH, salt-soluble protein concentration and myofibril fractions of beef extract was determined firstly, and no significant effect was found. The beef salt-soluble proteins extracted using salt solution at different concentrations were then added with elephant foot yam flour at 5%, 10%, and 15% w/w, gelatinized at 90℃ for 20 min, and cooled down at 4℃ for 12 h. The interactions between beef salt-soluble proteins and elephant foot yam flour resulted in an improved gel strength (p < 0.01) and the addition level of elephant foot yam flour affected the pH, instrumental color, moisture, crude protein, and ash content significantly. The addition of elephant foot yam flour also reduced the size of the pores in the gel matrix as shown by scanning electron microscope (SEM) photographs. These suggest that elephant foot yam flour well interacts with beef salt-soluble proteins to form gel matrix.

• Preventive Nutrition and Food Science
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• 제10권4호
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• pp.378-381
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• 2005

Actin and myosin solutions and fresh ground pork were irradiated with the electron beam (e-beam) at a dose of 0, 1.5, 3.0, 5.0 and 10 kGy. The changes in SDS-PAGE pattern of 2 proteins and the salt-soluble proteins extracted from ground pork after e-beam irradiation were monitored. When the myosin solution was irradiated with e-beam, myosin was degraded completely. Complete myosin degradations were observed even with the lowest dose (1.5 kGy) of e-beam treatment. Actin was degraded with the irradiation, but to a less extent than myosin was. The degradation of actin increased as the e-beam treatment increased from 1.5 to 10.0 kGy. Among the salt-soluble proteins extracted from ground pork, myosin was degraded gradually when the e-beam dose increased from 1.5 up to 10.0 kGy. Similar gradual increase in the degradation of actin also occurred with the increase of irradiation. Increases of 2 low molecular weight compounds (<29 kDa) were observed when the irradiation dose increased from 1.5 to 10.0 kGy. These 2 molecules are thought to be the breakdown products produced from the degradation of major salt-soluble proteins, myosin and actin. The salt-soluble protein content of ground pork did not change with the e-beam irradiation.

• 한국축산식품학회지
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• 제43권6호
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• pp.1031-1043
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• 2023

The purpose of this study was to investigate the functional properties of salt-soluble proteins obtained from Protaetia brevitarsis (PB) and Tenebrio molitor (TM) larvae, the interaction between these proteins and pork myofibrillar protein (MP) in a gel system. The gel properties of salt-soluble protein extracts showed that the PB had a higher viscosity than the TM protein. However, the TM protein had higher gel strength compared with the PB protein. The gelation characteristics of the pork MP gel systems added with lyophilized insect salt-soluble protein powder showed to decrease slightly viscosity compared with MP alone. Adding the TM or PB protein powder did not affect the pork MP's hydrophobicity and sulfhydryl group levels. Furthermore, the protein bands of the MP did not change with the type or amount of insect salt-soluble protein. The cooking yields of the pork MP gels containing PB or TM protein powder were higher than those without insect protein. Regardless of the type of insect salt-soluble protein added, the pork MP's gel strength decreased. Furthermore, as the level of insect powder increased, the surface protein structure became rough and porous. The results demonstrated that proteins extracted from PB and TM larvae interfered with the gelation of pork MP in a gel system.

• Parasites, Hosts and Diseases
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• 제52권4호
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• pp.367-376
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• 2014

Recombinant antigenic proteins of Toxoplasma gondii are alternative source of antigens which are easily obtainable for serodiagnosis of toxoplasmosis. In this study, highly antigenic secretory organellar proteins, dense granular GRA2 and GRA3, rhoptrial ROP2, and micronemal MIC2, were analyzed by bioinformatics approach to express as water-soluble forms of antigenic domains. The transmembrane region and disorder tendency of 4 secretory proteins were predicted to clone the genes into pGEX-4T-1 vector. Recombinant plasmids were transformed into BL21 (DE3) pLysS E. coli, and GST fusion proteins were expressed with IPTG. As a result, GST fusion proteins with $GRA2_{25-105}$, $GRA3_{39-138}$, $ROP2_{324-561}$, and $MIC2_{1-284}$ domains had respectively higher value of IgG avidity. The $rGST-GRA2_{25-105}$ and $rGST-GRA3_{39-138}$ were soluble, while $rGST-ROP2_{324-561}$ and $rGST-MIC2_{1-284}$ were not. $GRA2_{31-71}$, intrinsically unstructured domain (IUD) of GRA2, was used as a linker to enhance the solubility. The $rGST-GRA2_{31-71}-ROP2_{324-561}$, a chimeric protein, appeared to be soluble. Moreover, $rGST-GRA2_{31-71}-MIC2_{1-284}$ was also soluble and had higher IgG avidity comparing to $rGST-MIC2_{1-284}$. These 4 highly expressed and water-soluble recombinant antigenic proteins may be promising candidates to improve the serodiagnosis of toxoplasmosis in addition to the major surface antigen of SAG1.

• 한국잠사곤충학회지
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• 제33권1호
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• pp.1-5
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• 1991

누에알의 배자발율 단계별 가용성 단백질과 불용성 단백질에 대한 native-PAGE와 SDS-PAGE 분석을 하였다. 가용성 단백질의 대부분은 ESP, vitellin, 30K 단백질로 구성되어 있었고 배자발육 시기별 난황단백질의 변화는 native-PAGE와 SDS-PAGE에서 일치하였다. 배자발생의 후기에는 난황단백질의 분해산물로 보이는 수개의 peptides가 검출되었고 침산처리 후 1일된 알에서 1개의 특이한 단백질이 출현하였다. 누에알 마쇄물의 원심침전물에 대한 SDS-FAGE 분석결과 수종의 peptides가 배자발육의 진전과 함께 새로이 검출되었다.

• 한국식품영양과학회지
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• 제26권2호
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• pp.180-185
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• 1997

과실의 연화중에 단백질과 polygalacturonase의 변화에 대해 연구하고자 감과 대추에서 용해성 에 따라 추출한수용성 단백질, 염가용성 단백질 및 세포벽 단백질중의 polygalacturonase 활성 변화와 polygalacturonase pattern 변화를 조사하였다. 감과 대추의 연화 동안에 polygalacturonase 활성은 수용성 단백질과 염가용성 단백질분획에서는 증가하였고, 세포벽 단백질분획에서는 다소 감소하는 경향을 보였다. 완숙감의 수용성 단백질과 염가용성 단백질을 gel filtration한 경우 polygalacturonase는 두 단백질 모두 fraction No. $30{\sim}40$, $40{\sim}50$ 사이 2개의 활성 peak를 나타내었고, 연시의 경우에도fraction No. $35{\sim}50$ 사이 1개의 peak로 근 변화가 없었다. 또한 대추의 수용성 단백질과 염가용성 단백질을 gel filtration한 경우 완숙대추, 연화대추 모두 유사한 1개의 활성 Peak를 나타내었다. 한편 감과 대추의 세포벽 단백질을 gel filtration한 경우 연화에 따른 활성 peak는 수용성 단백질과 염가용성 단백질의 활성 peak와 거의 동일한 fraction에서 존재하였다. 이상의 연구결과로 보아서 감과 대추의 연화동안에 나타나는 polygalacturonase의 활성 증가는 과실의 성숙·연화에 따른 새로운 효소 단백질의 합성 및 두 과실의 세포벽에 결합된 비활성 형의 Polygalacturonase가 세포벽 단백질의 유리에 따라 활성 형으로 전환됨 에 따른 것으로 생각된다.

• 한국식물병리학회지
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• 제10권4호
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• pp.305-313
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• 1994

Typically susceptible lesions were developed on pepper (cv. Hanbyul) leaves inoculated with the compatible strains Ds 1 of Xanthomonas campestris pv. vesicatoria. The lesions appeared first water-soaked and then turned yellow with a chlorotic area. In contrast, the leaves inoculated with the incompatible strain 81-23 initially turned yellow and then developed local necrosis. Multiplication of x. c. pv. vesicatoria in pepper leaves also were distinctly different between the two strains. The strain Ds 1 multiplied more greatly than did the strain 81-23 in the infected leaves. X. c. pv. vesicatoria infection of pepper leaves induced the synthesis of soluble proteins, especially more greatly in the compatible than in the incompatible interactions. Some pathogenesis-related (PR) proteins were detected in the intercellular washing fluid (IWF) and extracts of the infected pepper leaves. In particular, the 32 kDa protein on SDS-PAGE gels appeared intensely in the incompatible interaction. In contrast, some proteins with moluecular masses of 65, 71, and 75 kDa disappeared in the infected pepper leaves. Isoelectric focusing could identify the pIs of soluble proteins in infected pepper leaves. The accumulation of the IWF from infected leaves was more conspicuous in the incompatible than the compatible interaction. These results suggest that some extremely acidic and basic proteins were induced and accumulated in the intercellular spaces of infected pepper leaves.

• Biotechnology and Bioprocess Engineering:BBE
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• 제6권6호
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• pp.395-401
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• 2001

Crystallins are a family of water-soluble proteins that constitute up to 90% of the wa-ter-soluble proteins in mammalian eye lenses, We present in this paper an alternative purification method for these proteins using polyethylene glycol/dextran aqueous two-phase extraction. Un-der the appropriate conditions, we were able to recover the γ-crystallin fraction essentially free of the remaining proteins. High concentrations of salt at a neutral pH maximize the recovery of γ-crystallins in the top phase and minimize the contamination by the other proteins present in the lenses. The proposed protocol decreases the separation time by about 50%. The complex partition behavior observed for these proteins reflects a delicate balance between protein/phase-forming species(various polymers and salts) and protein interactions. This is evidenced, in part, by the role played by the largest proteins in this group as a "pseudo"phase-forming species.