• 한국응용과학기술학회지
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• 제17권3호
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• pp.158-166
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• 2000

A conductimetric study of foam formed from mixture of the protein, ${\beta}-lactoglobulin$, and the nonioinc surfactant, SML, revealed that their stability was reduced at concentrations of SML in the range $3{\sim}10mM$. The interaction of SML with ${\beta}-lactoglobulin$ was investigated by fluorimetry and a dissociation constant of $0.2{\mu}M$ was calculated for the complex. Surface tension studies confirmed the presence of interaction between the two components and provided evidence for the progressive displacement of ${\beta}-lactogloblin$ from the air/water interface with increasing SML concentration. Experiments using air-suspended microscopic thin liquid films revealed transitions in the chainage characteristics and thickness of the film at SML concentrations below that which resulted in destabilization of the foam. However, measurements of surface mobility of fluorescent-labeled ${\beta}-lactoglobulin$ by a photobleaching method identified that a transition to a mobile system occurred at a SML concentration which correlated with the onset of instability in the disperse phase. The results would indicate that maintenance of the viscoelastic properties of the surface is paramount importance in determining the stability of interfaces comprising mixtures of protein and surfactant.

• 생명과학회지
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• 제20권11호
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• pp.1656-1661
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• 2010

난황단백질 가수분해를 위한 알칼리성 단백질분해효소를 5가지 담체 Duolite A568, Celite R640, Dowex-1, Dowex 50W 그리고 Silica gel R60 에 고정화하였다. Duolite A568의 경우에 24.7%의 최대 고정화 효율을 나타내었다. 자유 효소와 고정화 효소에 대한 최적의 pH는 각각 8과 9였고, 최적의 pH는 고정화에 의해 염기성으로 1만큼 증가하였다. 그러나 최적 온도는 자유 효소와 고정화 효소 모두 $50^{\circ}C$로 같았다. 고정화 효소가 자유 효소에 비해 높은 열 안정성을 보였다. 재사용 회분식 공정에서 10 cycle 동안 효소활성은 초기 활성의 86%를 유지하였다. 연속 공정을 위한 충진층 반응기에서 여러 유속에 대한 장기 조업에서 효소 활성의 안정성 평가하였는데 낮은 유속일수록 높은 활성을 유지하였다. 연속 조업에서 casein과 난황 단백질을 사용하여 원료에 대한 고정화 효소의 활성에 대한 영향을 조사하였다. 96시간 연속 조업에서 casein의 경우는 초기 활성의 83%를 유지하였고 난황 단백질의 경우는 초기 활성의 61%를 유지하였다.

• 한국식품과학회지
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• 제14권1호
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• pp.43-48
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• 1982

말쥐치 및 도루묵을 보다 효과적으로 이용하기 위하여, 축육과 유사한 텍스쳐를 가진 어육단백질농축물 저장 중의 품질 안정성 및 이용방안에 대하여 검토하였다. 제품은 함기포장하여 상온에 저장하여도 복수성, TBA값 및 갈변도 등에 큰 변화없이 90일간 품질이 안정하게 유지되었다. 햄버어그 및 튀김어단을 만들때 쇠고기 대신에 축육과 유사한 텍스쳐를 가진 어육단백질농축물을 50%까지 섞어도 맛, 냄새 및 텍스쳐 등에 별다른 손색이 없었다.

• Journal of Microbiology and Biotechnology
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• 제29권2호
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• pp.235-243
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• 2019

A special eosinophilic agarase exo-type ${\beta}$-agarase gene, AgaDL6, was cloned from a marine agar-degrading bacterium, Flammeovirga sp. HQM9. The gene comprised 1,383-bp nucleotides encoding a putative agarase AgaDL6 of 461 amino acids with a calculated molecular mass of 52.8 kDa. Sequence analysis revealed a ${\beta}$-agarase domain that belongs to the glycoside hydrolase family (GH) 16 and a carbohydrate-binding module (CBM_4_9) unique to agarases. AgaDL6 was heterologously expressed in Escherichia coli BL21 (DE3). Enzyme activity analysis of the purified protein showed that the optimal temperature and pH of AgaDL6 were $50^{\circ}C$ and 3.0, respectively. AgaDL6 showed thermal stability by retaining more than 98% of activity after incubation for 2 h at $50^{\circ}C$, a feature quite different from other agarases. AgaDL6 also exhibited outstanding acid stability, retaining 100% of activity after incubation for 24 h at pH 2.0 to 5.0, a property distinct from other agarases. This is the first agarase characterized to have such high acid stability. In addition, we observed no obvious stimulation or inhibition of AgaDL6 in the presence of various metal ions and denaturants. AgaDL6 is an exo-type ${\beta}$-1,4 agarase that cleaved agarose into neoagarotetraose and neoagarohexaose as the final products. These characteristics make AgaDL6 a potentially valuable enzyme in the cosmetic, food, and pharmaceutical industries.

• Journal of Animal Science and Technology
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• 제63권1호
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• pp.170-179
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• 2021

This study was conducted to determine the effects of addition of porcine blood plasma (PBP) to the emulsified pork batter as a substitute for the soy protein isolate (SPI) or sodium caseinate (SC) on the emulsion stability and physicochemical and textural properties of the emulsified pork batter. A total of 10 treatments were no addition and 0.5%, 1.0%, and 1.5% addition with each of SPI, SC, and PBP. The moisture and fat losses of the pork emulsion after cooking decreased with increasing percentage of any of SPI, SC, and PBP (p < 0.05). Further, moisture loss was less for the PBP treatment than for SPI and SC (p < 0.05). The lightness, redness, and whiteness of the emulsified pork batter decreased (p < 0.05) due to any of the SPI, SC, and PBP treatments whereas the yellowness and the chroma and hue values increased. The lightness, redness, yellowness, and chroma and hue values differed also among the SPI, SC, and PBP treatments (p < 0.05); however, the numerical difference between any two types of substitutes was less than 8% of the two corresponding means in all of these variables. Textural properties, including the hardness, cohesiveness, springiness, gumminess, chewiness, and adhesiveness, were not influenced by any of the SPI, SC, and PBP treatments (p > 0.05), except for greater gumminess and chewiness for the PBP treatment than for SC. The present results indicate that PBP is comparable or even superior to SPI or SC in its emulsion-stabilizing effect and therefore could be used a substitute for the latter as a non-protein ingredient of pork emulsion batter.

• Journal of Microbiology and Biotechnology
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• 제31권12호
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• pp.1732-1740
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• 2021

Tobacco etch virus protease (TEVp) is a useful tool for removing fusion tags, but wild-type TEVp is less stable under oxidized redox state. In this work, we introduced and combined C19S, C110S and C130S into TEVp variants containing T17S, L56V, N68D, I77V and S135G to improve protein solubility, and S219V to inhibit self-proteolysis. The solubility and cleavage activity of the constructed variants in Escherichia coli strains including BL21(DE3), BL21(DE3)pLys, Rossetta(DE3) and Origami(DE3) under the same induction conditions were analyzed and compared. The desirable soluble amounts, activity, and oxidative stability were identified to be reluctantly favored in the TEVp. Unlike C19S, C110S and C130S hardly impacted on decreasing protein solubility in the BL21(DE3), but they contributed to improved tolerance to the oxidative redox state in vivo and in vitro. After two fusion proteins were cleaved by purified TEVp protein containing double mutations under the oxidized redox state, the refolded disulfide-rich bovine enterokinase catalytic domain or maize peroxidase with enhanced yields were released from the regenerated amorphous cellulose via affinity absorption of the cellulose-binding module as the affinity tag.

• Journal of Microbiology and Biotechnology
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• 제21권2호
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• pp.183-186
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• 2011

Biochemical methods were selected to evaluate the role of exopolymeric substances in the stability of biofilms used in bioremediation processes. Biofilms of Thiomonas arsenivorans formed on pozzolana were thus treated with pronase (protein target), lectins (Con A or PNA), calcofluor or periodic acid (polysaccharides target), DNase (DNA target), and lipase (triglycerides target). Neither protease nor DNase treatments had any effect on bacterial adhesion. Lectins and calcofluor treatments mainly affected young biofilms. Lipase treatment had a noticeable effect on biofilm stability whatever the biofilm age. Results suggest that it would be an increased resistance of mature biofilms that protects them from external attacks.

• 한국식품영양과학회지
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• 제26권6호
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• pp.1102-1108
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• 1997

Proteins and polysaccharides confer distinct functional properties in food systems. This research was attempted to improve emulsion properties of casein by protein-polysaccharide conjugation, in which alginates with various molecular weights were employed as polysaccharide sources. Casein-alginate mixtures were conjugated by the amino-carbonyl or Maillard reaction at 6$0^{\circ}C$ and 79% relative humidity. The resulting casein-alginate conjugates were tested for their emulsion activity and emulsion stabilizing properties. In general, the emulsion stability of casein-alginate mixture greatly increased due to the amino-carbonyl reaction between casein and alginates, whose magnitude depended on the molecular weight of alginate, weight ratio of casein to alginate and incubation time. It was also found that thermal stability and pH stability were markedly improved by the casein-alginate conjugation.

• Molecules and Cells
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• 제27권6호
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• pp.629-634
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• 2009

G protein-coupled receptors (GPCRs) are part of multi-protein networks called 'receptosomes'. These GPCR interacting proteins (GIPs) in the receptosomes control the targeting, trafficking and signaling of GPCRs. PDZ domain proteins constitute the largest protein family among the GIPs, and the predominant function of the PDZ domain proteins is to assemble signaling pathway components into close proximity by recognition of the last four C-terminal amino acids of GPCRs. We present here a machine learning based approach for the identification of GPCR-binding PDZ domain proteins. In order to characterize the network of interactions between amino acid residues that contribute to the stability of the PDZ domain-ligand complex and to encode the complex into a feature vector, amino acid contact matrices and physicochemical distance matrix were constructed and adopted. This novel machine learning based method displayed high performance for the identification of PDZ domain-ligand interactions and allowed the identification of novel GPCR-PDZ domain protein interactions.

• BMB Reports
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• 제51권10호
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• pp.484-485
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• 2018

Receptor-interacting protein kinase-3 (RIP3 or RIPK3) is a serine-threonine kinase largely essential for necroptotic cell death; it also plays a role in some inflammatory diseases. High levels of RIP3 are likely sufficient to activate necroptotic and inflammatory pathways downstream of RIP3 in the absence of an upstream stimulus. For example, we have previously detected high levels or RIP3 in the skin of Toxic Epidermal Necrolysis patients; this correlates with increased phosphorylation of MLKL found in these patients. We have long surmised that there are molecular mechanisms to prevent anomalous activity of the RIP3 protein, and so prevent undesirable cell death and inflammatory effects when inappropriately activated. Recent discovery that Carboxyl terminus of Hsp 70-Interacting Protein (CHIP) could mediate ubiquitylation- and lysosome-dependent RIP3 degradation provides a potential protein that has this capacity. However, while screening for RIP3-binding proteins, we discovered that pellino E3 ubiquitin protein ligase 1 (PELI1) also interacts directly with RIP3 protein; further investigation in this study revealed that PELI1 also targets RIP3 for proteasome-dependent degradation. Interestingly, unlike CHIP, which targets RIP3 more generally, PELI1 preferentially targets kinase active RIP3 that has been phosphorylated on T182, subsequently leading to RIP3 degradation.