• 한국식생활문화학회지
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• 제14권5호
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• pp.477-485
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• 1999

This study was conducted to improve the functional properties of soybean protein isolate by dimethylglutarylation and acetylation. Amino acid composition and solubility of modified soybean protein by dimethylglutarylation were not changed, but lysine and trypsin inhibitor activity was decreased an isoelectric point was moved from pH5 to pH4 as a result of modification. Emulsification capacity and stability, foaming capacity and thermal stability were increased by the modification. In that 91% dimethylglutarylated protein did not coagulate when heating at $100^{\circ}C$ for 20 min. while its foaming stability was decreased. Whereas specific gravity was decreased by the modification of the soybean protein, relative viscosity and whiteness were improved. Generally, dimethylglutarylation produced more conformational changes in protein system than did in acetylation.

• Asian-Australasian Journal of Animal Sciences
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• 제16권8호
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• pp.1158-1164
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• 2003

In two feeding experiments male and mixed-sex broiler chicks were offered diets based on sorghum and a wheatsorghum blend with two tiers of nutrient specifications, without and with microbial phytase (600 and 800 FTU/kg), from 7-25 and 1-42 days post-hatch, respectively. The nutrient specifications for protein, amino acids, energy density and phosphorus (P) of standard diets were reduced to formulate the modified diets on a least-cost basis. Calculated differences in nutrient specifications between standard and modified diets ranged from 14.3 to 17.1 g/kg crude protein, 0.24 to 0.40 MJ/kg apparent metabolisable energy (AME) and 1.06 to 1.20 g/kg available P. In both experiments, reduced nutrient specifications had a negative impact on growth rates and feed efficiency and phytase supplementation had a positive influence on growth performance and protein efficiency ratios (PER). Phytase addition to the less expensive, modified diets either partially or entirely compensated for reduced growth performance and, consequently, feed costs per kg of live weight gain were reduced. In Experiment 1, phytase increased (p<0.001) nitrogen-corrected AME (AMEn) from 15.39 to 15.89 MJ/kg dry matter. For nitrogen (N) retention there was an interaction (p<0.05) between diet type and phytase as the effects of phytase on N retention were more pronounced in the modified diets, with an increase from 0.512 to 0.561. These results demonstrate the positive effects of phytase on protein and energy utilisation, in addition to its established liberation of phytate-bound P and illustrate the feasibility of assigning nutrient replacement values to the feed enzyme for consideration in least-cost ration formulations. Further work is, however, required to define the most appropriate reductions in nutrient specifications in association with phytase supplementation.

• 농업과학연구
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• 제45권2호
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• pp.248-257
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• 2018

Overexpression of AtCYP78A7, a gene encoding a cytochrome P450 protein, has been reported to improve tolerance to drought stress in genetically modified (GM) rice (Oryza sativa L.). The aim of this study was to evaluate the potential allergenicity and acute oral toxicity of the AtCYP78A7 protein expressed in GM rice. Bioinformatics analysis of the amino acid sequence of AtCYP78A7 did not identify any similarities with any known allergens or toxins. It showed that no known allergen had more than a 35% amino acid sequence homology with the AtCYP78A7 protein over an 80 amino acid window or more than 8 consecutive identical amino acids. The gene encoding the AtCYP78A7 protein was cloned in the pGEX-4T-1 vector and expressed in E. coli. Then, the AtCYP78A7 protein was purified and analyzed for acute oral toxicity. The AtCYP78A7 protein was fed at a dose of 2,000 mg/kg body weight in mice, and the changes in mortalities, clinical findings, and body weight were monitored for 14 days after the dosing. Necropsy was carried out on day 14. The protein did not cause any adverse effects when it was orally administered to mice at 2000 mg/kg body weight. These results indicate that the AtCYP78A7 protein expressed in GM rice would not be a potential allergen or toxin.

• BMB Reports
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• 제41권3호
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• pp.194-203
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• 2008

Nitrosative modifications regulate cellular signal transduction and pathogenesis of inflammatory responses and neuro-degenerative diseases. Protein tyrosine nitration is a biomarker of oxidative stress and also influences protein structure and function. Recent advances in mass spectrometry have made it possible to identify modified proteins and specific modified amino acid residues. For analysis of nitrated peptides with low yields or only a subset of peptides, affinity 'tags' can be bait for 'fishing out' target analytes from complex mixtures. These tagged peptides are then extracted to a solid phase, followed by mass analysis. In this review, we focus on protein tyrosine modifications caused by nitrosative stresses and proteomic methods for selective enrichment and identification of nitrosative protein modifications.

• 대한가정학회지
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• 제28권4호
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• pp.41-50
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• 1990

Soy protein was isolated from Korean soy bean 'Chang ryub' and chemically modified with succinic anhydride. Functionality of the soy protein isolate(SPI), succinylated SPI(SPPI), and PP590(commercial) at various pH were investigated. The mechanical and sensory properties of soy bean curds made from several mixing ratio of succinylated soy bean milk were observed. The solubility of SPI significantly increased with succinylation. The solubility of PP590 was lower than that of SSPI. The solubility of SPPI increased significantly in 0.03M CaCl2 solution. The emulsifying activity of SSPI increased. On the range of pH above pI the emulsifying activity of PP590 was higher than that of SPI. There was no difference in emulsion stability among the groups. The foam expansion capacity of SPPI increased at higher pH than pI but the foam stability decreased significantly above pH 9. Mechanical texture profile analysis revealed the modified soy bean curds had the lower hardniss, chewiness and cohesiveness with increased modification. The mechanical characteristics of modified soy bean curds revealed generalized Maxwell Model of 7-elements or 5-elements. In sensory evaluation, the hardness, the springiness and acceptability of modified soy bean curds were lower significantly than those of control soy bean curd.

• 한국식품과학회지
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• 제24권3호
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• pp.294-299
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• 1992

본 연구에서는 분리대두단백질에 단백질 가수분해효소를 처리하여 대두단백질에 가수분해적 변성을 야기하여 그 기능성을 변화 고찰하고 실제 식품에의 이용방법으로 효소처리된 두유로 두부를 만들어 물성실험과 관능평가를 실시하였다. 장엽에서 SPI를 제조한 후 15분간 bromelain으로 처리하여 2.7% 가수분해된 MSPI를 만들어 기능특성을 측정 비교하였다. MSPI는 전 pH범위에서 용해도가 증가하였고, 특히 등전점에서 15% 정도 증가하였다. 유화형성력과 기포팽창력은 증가하였으나 이들의 안정성은 감소하였는데, 특히 기포안정성은 알칼리쪽에서 급격히 감소하였고, 등전점에서는 가장 큰 것으로 나타났다. 표준두유와 변형두유를 혼합하여 제조한 두부로 물성실험과 관능평가를 실시하였을 때 압착실험에서는 변형두부I이 연하고 탄력성 있는 두부를 형성하는 것으로 나타났다. 각 두부의 물성모형은 spring 한개와 Maxwell 모형 세개를 가진 7요소모형으로 동일한 물성모형을 나타내었다. 관능평가에서는 표준두유와 변형두유를 3 : 1의 비율로 혼합하여 제조한 두부의 품질이 가장 우수한 것으로 평가되었다.

• Journal of Microbiology and Biotechnology
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• 제12권2호
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• pp.306-311
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• 2002

O-linked N-acetylglucosamine (O-GlcNAc) is an abundant posttranslationally modified compound in eukaryotic cells. Human O-GlcNAc transferase (OGT) was produced as a maltose binding protein (MBP) fusion protein, which showed significant catalytic activity to modify recombinant Sp1, transcription factor. To facilitate the production of O-GlcNAc modified proteins, instead of using the tedious in vitro glycosylation reaction or expression in eukaryotic cells, a MBP-fusion OGT expression vector (pACYC184-MBPOGT) was constructed using pACYC184 plasmid, which could coexist with general prokaryotic expression vectors containing ColE1 origin. By cotransforming pACYC184-MBPOGT and pGEX-2T vectors into Escherichia coli BL21, intracellular O- GlcNAcylated proteins could be obtained by a simple purification procedure. It is expected that this may be a useful tool for production of O-GlcNAc modified proteins.

• Food Science and Biotechnology
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• 제18권1호
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• pp.60-65
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• 2009

Near infrared reflectance spectroscopy (NIRS) was used as a rapid and non-destructive method to determine the protein content in intact and ground seeds of pea (Pisum sativum L.) germplasms grown in Korea. A total of 115 samples were scanned in the reflectance mode of a scanning monochromator at intact seed and flour condition, and the reference values for the protein content was measured by auto-Kjeldahl system. In the developed ground and intact NIRS equations for analysis of protein, the most accurate equation were obtained at 2, 8, 6, 1 math treatment conditions with standard normal variate and detrend scatter correction method and entire spectrum (400-2,500 nm) by using modified partial least squares regression (n=78). External validation (n=34) of these NIRS equations showed significant correlation between reference values and NIRS estimated values based on the standard error of prediction (SEP), $R^2$, and the ratio of standard deviation of reference data to SEP. Therefore, these ground and intact NIRS equations can be applicable and reliable for determination of protein content in pea seeds, and non-destructive NIRS method could be used as a mass analysis technique for selection of high protein pea in breeding program and for quality control in food industry.

• 한국식품과학회지
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• 제20권5호
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• pp.625-630
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• 1988

대두단백질을 인산화 및 초산화처리에 의하여 변형시키고, 변형대두단백질의 기능특성을 검토하였다. 인산화 대두단백질은 비변형 대두단백질보다 높은, 용해도, 거품특성, 수분보유력을 나타냈다. 한편, 초산화에 의해서도 유화력과 거품특성이 현저하게 증진되었다. 대두단백질은 인산화와 초산화에 의하여 등전점이 산성쪽으로 변화였으며 단백질의 집괴화현상도 관찰되었다. 또한, 화학변형된 대두단백질을 디스크 전기영동에 의해 분석시 단백질밴드의 상대이동도가 현저하게 증대되었다.

• 한국식품영양과학회지
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• 제19권3호
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• pp.219-223
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• 1990

Myofibrillar protein from Alaska pollack was modified with acetic anhydride at pH 7.5 and $25^{\circ}C$ and changes in functional properties as affected by the degree of modification were determined. Acetylation of myofibrillar protein resulted in protein with unique functional properties dependent upon the degree of acetylation. By selecting appropriate degree of modification it was possible to control protein solubility heat coagulability calcium precipitability foaming and emulsion capa-city.