• Biotechnology and Bioprocess Engineering:BBE
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• 제11권3호
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• pp.215-222
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• 2006

The Lowry method was used in this study to measure protein in Haemophilus influenzae type b (Hib) conjugate vaccines (polyribosylibitol phosphate-tetanus toxoid; PRP-TT) using deoxycholic acid (DOC) to induce protein precipitation. Trichloroacetic acid (TCA) did not induce precipitation adequately from the Hib conjugate bulk and the freeze-dried Hib conjugate product. Its yield was approximately 50%. The matrix structure of Hib conjugate inhibits precipitation by TCA. Although the Lowry method can be carried out without precipitation in Hib conjugate bulk when no residual impurities (adipic acid dihydrazide [ADH], 1-ethyl-3-(3-dimethylamino-propyl) carbodiimide-HCI [EDAC], phenol and cyanogens bromide [CNBr], etc.) are present, it cannot be used for Hib conjugate products that contain sucrose 8.5%, because 8.5% concentration of sucrose enhanced the protein concentration. DOC- and HCl-induced precipitation is an alternative method for evaluating the protein content of the Hib conjugate bulk and the Hib conjugate product. The precipitation was optimal with a final concentrate of 0.1% for DOC at $4^{\circ}C$ and pH 2. This Lowry method, using DOC/HCI precipitation to induce protein precipitation, was confirmed a consistent, reproducible, and valid test for proteins in Hib conjugate bulk and its freeze-dried product.

• Macromolecular Research
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• 제11권1호
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• pp.53-61
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• 2003

A molecular-thermodynamic model is developed for the salt-induced protein precipitation. The protein molecules interact through four intermolecular potentials. An equation of state is derived based on the statistical mechanical perturbation theory with the modified Chiew's equation for the fluid phase, Young's equation for the solid phase as the reference system and a perturbation based on the protein-protein effective two body potential. The equation of state provides an expression for the chemical potential of the protein. In a single protein system, the phase separation is represented by fluid-fluid equilibria. The precipitation behaviors are simulated with the partition coefficient at various salt concentrations and degree of pre-aggregation effect for the protein particles. In a binary protein system, we regard the system as a fluid-solid phase equilibrium. At equilibrium, we compute the reduced osmotic pressure-composition diagram in the diverse protein size difference and salt concentrations.

• Journal of Oral Medicine and Pain
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• 제20권1호
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• pp.7-18
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• 1995

The Purpose of this article is to describe the biochemical properties and biological functions of several salivary proteins that possess the unusual properties of inhibiting spontaneous and secondary precipitation of calcium phosphate. This function is very important since human salivary secretion is supersaturated with respect to calcium phosphate. Biological function of statherin, proline rich protein (PRP) and histidine rich protein (HRP) is to inhibit precipitation of calcium phosphate in salivary glands, in the oral fluids, and onto tooth surfaces. The resulting supersaturated state of the salivary secretions contributes a protective and reparative environment which is important for the integrity of the tooth. Beneficial consequences of salivary supersaturation with respect to calcium phosphate are selectively expressed in the oral cavity- that is, protection is provided for the dental enamel-while undesirable consequences, for example, precipitation of calcium phosphates in the salivary glands and onto the teeth do not occur. Purification and structural characteristics of these proteins as well as clinical significance of functions of each protein will be discussed.

• Journal of Applied Biological Chemistry
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• 제51권3호
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• pp.88-94
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• 2008

Three different protein extraction methods-phenol extraction, trichloroacetic acid (TCA) precipitation, and desalting/TCA precipitation-were compared to determine the optimal reproducible high resolution 2-dimensional (2-D) electrophoresis for each chungkugjang, doenjang, and kochujang samples. The soluble proteins from Chungkugjang extracted by phenol were separated with high reproducibility and resolution, and gained 1.75- to 3-fold more protein spots on 2-D gel than those from the other methods. On the contrary, the extracted proteins from doenjang and kochujang treated by desalting/TCA precipitation method showed about 1.5- to 3.3-fold more protein spots on 2-D gel. Using the established methods, the changes in the protein profiles of the fermented soy foods were monitored during the fermentation period by 2-DE. One of the major proteins in soy, $\beta$-conglycinin $\alpha$-subuint, and some proteins with unknown functions were localized on 2-D gel as the protease-resistant proteins throughout the fermentation period of doenjang. Changes in the protein profile monitored by the established methods can provide basic information on unfolding the mechanisms of the generation of biofunctional activity in the fermented soy foods.

• 동아시아식생활학회지
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• 제10권5호
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• pp.394-403
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• 2000

The functional properties of sesame protein concentrate(SPC) using different size of ultrafiltration(UF) membranes were examined and compared with those of conventional acid-precipitated sesame protein concentrate. The protein contents of SPC by UF with molecular size of 10K, 30K and look dalton membranes were 84.2%, 82.7%, and 76.4%, respectively, and that of acid-precipitated SPC was 88.7%. The nitrogen solubility of SPC by UF was higher than that of conventional SPC at various pH levels. Especially, it showed three-fold increase at near isoelectric point. However, water absorption capacity and fat absorption capacity of SPC by UF were decreased. For emulsion and foam properties, there were no significant differences between SPC by acid precipitation and SPC by UF method. At various pH levels, SPC by membrane with pore size of 30K dalton showed the highest emulsion properties. The SPC by UF had slightly higher viscosity than defatted sesame flour and SPC by acid precipitation.

• 한국수소및신에너지학회논문집
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• 제17권4호
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• pp.371-378
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• 2006

Effect of $(NH_4)_2SO_4$ precipitation and heat-treatment on hydrogenase which was extracted from the cytoplasmic fraction of the phototrophic purple sulfur bacterium Thiocapsa roseopersicina NCIB 8347 was studied. Crude enzyme extract was prepared by centrifugation($28,000{\times}g$, $400,000{\times}g$) after sonication of cells grown under photosynthetic condition for 96 hrs. Various conditions of $(NH_4)_2SO_4$ precipitation and heat-treatment were examined and the effect of protein concentration was analyzed by SDS-electrophoresis between the treatments. Optimum conditions for $(NH_4)_2SO_4$ precipitation and heat-treatment for evolution hydrogenase activity were 40-60% saturation and $60^{\circ}C$ for 20 min, respectively, which exhibited the specific hydrogenase activity of 0.78 U/mg-protein. Specific hydrogenase activity was decreased to 31.6% when the heat-treatment at $60^{\circ}C$ increased from 20 min to 5 hrs.

• Macromolecular Research
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• 제11권4호
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• pp.241-249
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• 2003

A molecular-thermodynamic model to describe the salt-induced protein precipitation is developed based on the perturbation theory. We employed the modified perturbed hard-sphere-chain (PHSC) equation of state for copolymer mixtures to take into account the pre-aggregation effect among protein particles. Hypothetical pressure-composition diagrams are computed with various size differences and salt concentrations. The precipitation behaviors are also studied for various types of pre-aggregation effect for the given systems.

• Bulletin of the Korean Chemical Society
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• 제33권7호
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• pp.2156-2162
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• 2012

Many literatures focus on the biological relevance and the identification of biomarkers for disease activity assessment while less attention has been paid to the development of standard procedures for sample preparation and storage based on liquid chromatography technique. The influencing factors including protein precipitation, storage temperature, storage time, and reconstitution by ultra pure water were analyzed employing HPLC-DAD. The effects were investigated from five participants over three months by principal components analysis (PCA) and the values of percent changes (PC). The samples with protein precipitation might slow the rate of bacterial enzymatic conversion. After protein precipitation, the average PC of urine samples ($0.136{\pm}0.013$, n = 5) is relatively less than that of the serum samples ($0.173{\pm}0.026$, n = 5) for three months. Minimal effects on metabolic profiles of serum and urine (PC < 0.15) are reasonable for metabolomic studies after protein precipitation and storage at $-20^{\circ}C$ for two months.

• 한국식품영양학회지
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• 제3권2호
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• pp.207-210
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• 1990

Paper chromatography and (NH4)2SO4 precipitation method were used for refinement and separation of proteins Color reaction was tested by Biuret test, Million test, Xanthoprotein test, and Ninhydrin test. Precipitation reaction and coagulation of proteins were tested by heating method (Ethanol, HNO3).

• 대한약침학회지
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• 제25권2호
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• pp.114-120
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• 2022

Objectives: Antivenom serums have been used extensively for over a century and are the only effective treatment option for snake bites and other dangerous animal envenomations. In therapeutic serum centers, a wide range of antivenoms is made from animal serum, mainly equine and sheep, that are immunized with single or multiple venoms. This work aimed to use caprylic acid (CA) to purify therapeutic snake antivenom. Methods: Plasma was obtained from equine immunized with a mixture of venoms. Immunized plasma was obtained by precipitation of different concentrations (2-5%) of CA. This methodology was compared to that based on ammonium sulfate (AS) precipitation. Sediment plasma proteins were purified by ion-exchange chromatography. Protein assay, SDSPAGE, and agar gel diffusion were performed. Results: The total protein precipitation with AS was higher than precipitation with CA, but the best results were obtained when CA was added to the plasma until a final CA concentration of 5% was reached. Chromatography and electrophoresis indicated a stronger band for the 5% CA, and the gel diffusion assay showed antigen-antibody interaction in the purified serum. Conclusion: The use of CA compared to the routine method for purifying hyperimmune serums is a practical and cost-effective method for preparing and producing therapeutic serums. It constitutes a potentially valuable technology for alleviating the critical shortage of antivenom in Iran.