• 대한지역사회영양학회지
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• 제27권1호
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• pp.47-60
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• 2022

Objectives: This study aimed to evaluate dietary protein intake and its adequacy among Korean adults during recent 10 years. Methods: Based on the 2010 ~ 2019 Korea National Health and Nutrition Examination Survey (KNHANES) data, a total of 51,296 adults aged 19 years old or more who participated in a one-day 24-hr dietary recall were included. Dietary protein intake was estimated as percentages of total energy (% of energy) and grams per body weight (g/kg/day) and compared with the 2020 Dietary Reference Intakes for Koreans to evaluate the adequacy of protein intake. In addition, proportions of people whose protein intakes were less than the estimated average requirement (EAR) and above the upper limit of the acceptable macronutrient distribution range (AMDR) (> 20% of energy) were calculated according to sociodemographic characteristics. Results: Protein intake was increased from 14.7% of energy in 2010 to 15.6% of energy in 2019 among Korean adults. However, there was no increase in protein intake relative to the recommended nutrient intake (% RNI) during the recent 10 years. Protein intake relative to the RNI was decreased from 130.2% in 2010 to 121.1% in 2019 (P for trend < 0.0001) among total participants, and a significant decreasing trend was observed in all age groups except for over 65 years old. However, protein intake relative to the RNI was lowest in the elderly (98.6%). Proportions of low protein intake (< EAR) and high protein intake (> AMDR) increased in the past 10 years (P for trend < 0.0001 for all), and these were associated with socioeconomic statuses, such as education and household income levels. Conclusions: These findings suggest that protein adequacy in Korean adults has not been improved over the past decade compared with recommended levels. Nutritional education and intervention programs should consider different intake levels according to sociodemographic characteristics.

• Journal of Nutrition and Health
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• 제20권2호
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• pp.122-134
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• 1987

In order to investigate the effect of dietary protein and fat levels on the growth and the utilization of nitrogen and energy and body composition in rats, Sprague\ulcornerDawley 48 male rats of 8 weeks old weighing approxijIlately 215-220g were subjected to feeding trials for 8 weeks and then subsequently to metabolic trials for 2 weeks. Four dietary protein levels (4, 8, 16, 32%) and each protein level contained two fat levels(3.9, 11.7%=1O,3J% of 3600kcal ME/kg) by addition of an appropriate amount of carbo\ulcornerhydrate and the following results were obtained. The body weight gain and food efficiency ratio of the rats to which a diet of 16% protein and 3.9% fat was fed were significantly higher than in either case of 8% pro\ulcornertein diet or of 32% protein diet. The digestibility of protein in the experimental diets was 73.3 -93.4%. The digesti\ulcornerbility of energy ( energy absorption) in the experimental diets was 83.2 -91.5%. The utilization of protein and the metabolic energy efficiency in the experimental diets was highest at the diet of 8% protein and 3.9% fat. The analysis of the body composition after feeding trials for 8 weeks has shown that the content of body water and protein were not affected by protein and fat levels in diet. The content of body fat in the rats to which 3.9% fat diet was fed was high\ulcornerer than that in those to which 11.7% fat diet was fed. From the above experimental results it may be suggested that the best formula of diet for the 8 weeks old rats may be composed of the 8% protein and 3.9% fat.

• 폴리머
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• 제36권3호
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• pp.338-343
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• 2012

콘텍트렌즈용 하이드로젤의 계면 특성의 이해를 위해 단백질 흡착 현상을 열역학을 바탕으로 연구하였다. 다른 습윤성을 갖는 $1{\times}1mm^2$ 크기의 하이드로젤을 알부민(bovine serum albumin, BSA)용액에 1시간 동안 침지시킨 후 남아있는 BSA 용액의 농도를 Bradford assay로 정량하였다. 모든 하이드로젤로의 단백질 흡착량은 단백질 농도가 증가함에 따라 계면 흡착량이 증가하며 Langmuir 곡선의 형태를 보였다. 또한 계면과 용액내의 단백질 농도비($P$), 계산된 흡착 Gibbs free energy는 하이드로젤 재료의 친수성도가 증가함에 따라 증가하였다. 표면에너지와 단백질 흡착량 상관관계를 이해하여 콘택트렌즈 재질로의 단백질 흡착현상의 물리화학적 해석이 가능함을 알 수 있었다.

• 한국가금학회지
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• 제14권1호
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• pp.1-8
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• 1987

사료의 에너지와 단백질 수준이 산란계의 능력에 미치는 영향을 조사하기 위하여 3회의 시험을 실시하였다. 시험1에서는 352일령의 마니나 브라운종을, 시험 2에서는 280일령의 갈색 와렌종을, 시험 3에서는 317일령의 갈색 와렌종을 각각 이용하였다. 각 시험에서 공히 총 360수의 공시계를 18수씩 20개구로 나누어 4개처리에 5반복으로 배치하였다. 시험 설계는 2가지 수준의 에너지(2500과 2800 kcal ME/kg)와 2가지 수준의 단백질 (13% 및 16 %)을 조합한 2$\times$2 요인시험을 실시하였다. 모든 공시계는 산란계용 Cage에 cage 당 2수씩 수용하였으며 시험 1과 2에서는 4주간의 시험기간동안 시험사료와 물을 자유로이 급여하였고 시험3에서는 2주간의 시험기간동안 사료섭취량을 1일 수당 130g으로 제한하여 급여하였다. 시험 1과 2에서 고에너지 사료를 섭취한 닭이 산란율이 다소 높았으나 유의성은 없었다. 그러나 시험 1에서는 단백질 수준이 산란율에 영향을 미치지 못하였다. 사료를 제한 급여한 시험3에서는 고에너지 사료에서 산란율이 개선되었으며(P〈0.05) 단백질 수준도 산란율에 영향을 미쳤으나 유의성은 없었다. 시험 1과 2에서 란중은 에너지 수준이나 단백질 수준에 의하여 영향을 받지 않았으나 시험 3에서는 고에너지 수준에서 란중도 약간 개선되는 경향을 보였다. 3회의 시험 모두에서 사료의 단백질이나 에너지 수준이 증가할 때 egg mass가 증가하는 경향을 보였다. 사료의 에너지나 단백질 수준이 증가할 때 사료섭취량은 감소하고 사료효율이 개선되는 경향을 보였다. 또한 사료의 에너지 수준이 증가할 때 단백질 효율(egg mass/단백질섭취량)이 개선되었으며 사료의 단백질 수준이 증가할 때 에너지 효율(egg mass /ME 섭취량) 이 개선되었다.

• Asian-Australasian Journal of Animal Sciences
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• 제16권10호
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• pp.1475-1481
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• 2003

The aim of this paper was to use the Cornell Net Carbohydrate and Protein System (CNCPS), that reports diet energy and protein value and animal requirements, as net energy for lactation ($NE_1$) and metabolizable protein (MP) respectively, to evaluate some rations for lactating Italian Mediterranean buffaloes. The investigation was carried out on six farms in the province of Caserta (southern Italy), where the milk production was controlled four times monthly on 10 animals (changing every time) chosen at different lactation days (5 categories): <2 months (A), 2-4 months (B), 4-6 months (C), 6-8 months (D), >8 months (E). Milk fat and protein were determined. Diet $NE_1$ and MP were estimated with the CPM-Dairy program (1998) using diet component chemical characteristics; then energy and protein intakes were estimated. $NE_1$ and MP requirements were estimated with two methods: 1) using CPM-Dairy that considers produced milk, fat and protein content, lactation phase and body condition score as main factors; 2) by applying the theory that to produce 1 kg of energy corrected milk, the buffalo needs 3.56 MJ of $NE_1$ and the efficiency to convert the absorbed aminoacids into milk protein is lower than cow (CNCPS). As regards energy, with method 1 the requirements were satisfactory starting from category A (4 out of 6 farms) and category B (5/6 farms); however, a surplus resulted for category E (5/6 farms). With method 2 a deficit in category A (5/6 farms) and B (3/6 farms) was observed, while the energy requirements were satisfied for all categories except E, where on only one buffalo farm had a surplus of energy intake. As regards protein, with method 1 the requirements were substantially satisfied for all the categories except E (3/6 farms); with method 2 the MP trend was much less favourable than with method 1. Indeed, a protein deficit was observed for all animals in categories A and B (5/6 farms). Moreover, on one farm the protein intake never satisfied animal requirements. In our experimental conditions, the use of the CNCPS to characterise diets for lactating buffalo and to calculate their requirements led to satisfactory results. By contrast, we cannot say the same for method 2, which applies a lower use efficiency of NE and MP for lactation in buffalo compared to cow.

• BMB Reports
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• 제45권12호
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• pp.700-706
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• 2012

Obesity is a worldwide epidemic as well as being a major risk factor for diabetes, cardiovascular diseases and several types of cancers. Obesity is mainly due to the overgrowth of adipose tissue arising from an imbalance between energy intake and energy expenditure. Adipose tissue, primarily composed of adipocytes, plays a key role in maintaining whole body energy homeostasis. In view of the treatment of obesity and obesity-related diseases, it is critical to understand the detailed signal transduction mechanisms of adipogenic differentiation. Adipogenic differentiation is tightly regulated by many key signal cascades, including insulin signaling. These signal cascades generally transfer or amplify the signal by using serial tyrosine phosphorylations. Thus, protein tyrosine kinases and protein tyrosine phosphatases are closely related to adipogenic differentiation. Compared to protein tyrosine kinases, protein tyrosine phosphatases have received little attention in adipogenic differentiation. This review aims to highlight the involvement of protein tyrosine phosphatases in adipogenic differentiation and the possibility of protein tyrosine phosphatases as drugs to target obesity.

• 수산해양교육연구
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• 제26권4호
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• pp.868-876
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• 2014

This study was conducted to estimate the optimum dietary protein to energy (P/E) ratio in juvenile river puffer. Nine experimental diets were formulated with three energy levels and three protein levels at each energy levels. Three energy levels of 3000, 3750 and 4500 kcal diets were included at 45, 50 and 55% crude protein (CP) levels, respectively (45P3000, 45P3750, 45P4500, 50P3000, 50P3750, 50P4500, 55P3000, 55P3750 and 55P4500). Fish averaging $3.43{\pm}0.02$ g randomly were fed the experimental diets in triplicate groups for 8 weeks. Weight gain of fish fed the 50P4500 diet were significantly higher than that of fish fed the 45P3000, 45P3750, 45P4500, 50P3000 and 50P3750 diets (P<0.05), but there was not significantly different from that of fish fed the 50P4500, 55P3750 and 55P4500 diets. Feed efficiency of fish fed the 50P4500 diet were significantly higher than that of fish fed the 45P3000, 45P3750, 45P4500, 50P3000 and 50P3750 diets (P<0.05), but there was not significantly different from that of fish fed the 50P4500, 55P3000, 55P3750 and 55P4500 diets. Protein efficiency ratio of fish fed the 45P3000 and 45P3750 diets was higher than that of fish fed 50P4500 and 55P4500, but there was not significantly different from that of fish fed the 45P3000, 45P3750, 45P4500, 50P3000, 50P3750, 55P3000 and 55P3750 diets. Based on weight gain, feed efficiency and specific growth rate, diets containing energy levels 4500 kcal/kg diet had an optimum P/E ratio of approximately 111 mg protein/kcal (50% crude protein) in juvenile river puffer.

• Asian-Australasian Journal of Animal Sciences
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• 제21권11호
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• pp.1629-1634
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• 2008

A trial was conducted to determine the effect of low crude protein (CP) diets with constant metabolizable energy to crude protein (ME:CP) ratio on growth, body composition and nutrient utilization of broiler chicks from 1 to 26 days of age. Four dietary treatments having four levels of CP and ME as 23, 22, 21 and 20% and 3,036, 2,904, 2,772 and 2,640 kcal/kg, respectively, were formulated and a ME:CP ratio of 132 was maintained in all the diets. Digestible lysine was maintained at 1.10 of the diet. A total of 1,760 day-old Hubbard broiler chicks were randomly divided into 16 experimental units and each diet was offered to four experimental units at random. Feed intake was increased (p<0.05) while weight gain and feed conversion ratio were adversely affected (p<0.05) when the diets with low CP and ME were fed to broilers. Total protein intake and total ME intake were linearly decreased (p<0.05) and protein efficiency ratio and energy efficiency ratio were lower (p<0.05) than in the chicks fed dietary regimen with 22% CP and 2,904 kcal/kg ME. The whole body analysis of the birds revealed that chicks fed the lowest dietary regimens retained less (p<0.05) nitrogen and more ether extract than chicks fed the control diet, however, body dry matter, total body ash and fat free body protein were not affected. Similarly, protein and energy utilization were also unaffected by the dietary treatments. In summary, chicks fed low CP diets with constant ME:CP ratio grew slower, used feed less efficiently and retained less protein and more body fat than chicks fed the control diet.

• Journal of Nutrition and Health
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• 제28권8호
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• pp.782-790
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• 1995

The longitudinal changes in protein secretion from 27 lactating women(primiparae = 10, multiparae=17) and protein intake of infants have been studied from 0.5 to 6 months postpartum in Chungju and Anseong area. The protein contents o breast milk in primiparae appeared significantly higher than in multipaae at 0.5 and 1 month postpartum. The protein secretion of primiparae and multiparae was not significantly different. In breast-feeding period, there was a tendency that protein secretion from 0.5 to 2 months postpartum was higher than thereafter. Average protein intake of boys from milk from 0.5 to 6 months postpartum was significantly higher than that of girls(p<0.05), because volume of milk intake of boys was much more than that of girls. In the amount of protein intake per infant weight, there was no significant difference between boys and girls. Protein intakes per infant weight decreased during lactation. Mean energy consumption of lactating women was 2,327㎉/day, which was 93.1% of recommended energy allowance for Koreans. Mean dietary protein consumption of lactating women was 81g/day, which was 101.3% of recemmended protein allowance for Koreans. Energy ratio of carbohydrate : protein : lipid was appeared to 68.8 : 13.9 : 17.3.

• EDISON SW 활용 경진대회 논문집
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• 제5회(2016년)
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• pp.163-166
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• 2016

Hydrophobicity is the key concept to understand the water plays in protein folding, protein aggregation, and protein-protein interaction. Traditionally, the hydrophobicity of protein is defined based on the scales of the hydrophobicity of residue, assuming that the hydrophobicity of free amino acids is maintained. Here, we explore how the hydrophobicity of constituting amino acids in protein rely on the protein context, in particular, on the total charge and secondary structures of a protein. To this end, we calculate and investigate the hydration free energy of three short proteins based on the integral-equation theory of liquids. We find that the hydration free energy of charged amino acids is significantly affected by the protein total charge and exhibits contrasting behavior depending on the protein total charge being positive or negative. We also observe that amino acids in the ${\beta}-sheets$ display more enhanced the hydrophobicity than amino acids in the loop, whereas those in the ${\alpha}-helix$ do not clearly show such a tendency. And the salt-bridge forming amino acids also exhibit increase of the hydrophobicity than that with no salt bridge. Our results provide novel insights into the hydrophobicity of amino acids, and will be valuable for rationalizing and predicting the strength of water-mediated interaction involved in the biological activity of proteins.