• Journal of Nutrition and Health
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• 제21권1호
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• pp.47-60
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• 1988

This study was performed to investigate the effect of dietary levels on protein metabolism in eight healthy Korean adult females. The 20-day metabolic study consisted of 2 day adaptation period and three 6-day experimental. Three experimental diets were low protein (LP : protein 44g), high protein(HP : protein 85g) and high animal protein (HAP : protein-84g). The apparent absorption and balance on nitrogen were significantly higher in high protein than in low protein diet. Nitrogen, absorption rate was about 75% for low protein and about 85% for high protein intake. The mean values of nitrogen balance were -1.28% for low protein and 0.78% for high protein diet. All the subjects were in negative nitrogen balance at the low protein intake while they were in positive nitrogen balance at the high protein intake. The mean daily urinary nitrogen excretion increased with increased level of protein intake. Urea nitrogen was the largest part of the urinary nitrogen. The ratio of urea nitrogen to total urinary nitrogen increased significantly for 79 to 85% as protein intake was doubled.

• 생명과학회지
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• 제6권3호
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• pp.185-192
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• 1996

박테리오파지 T7 gene 2.5 단백질은 single-stranded DNA 결합 단백질로 박태리오파지 T7의 DNA복제, 재조합, 및 수선에 필수적으로 요구된다. Gene 2.5 protein은 T7의 DNA 합성과 성장에 필수적인 단백질이다. Gene 2.5 Protein이 중요시 되는 이유는 이 단백질이 T7의 다른 복제 필수단백질인 T7의 다른 복제 필수단백질인 T7 DNA polymerase 와 gene 4 protein(helicase/primase)와 서로 상호작용할 것으로 제안되었기 때문이다. (Kim and Richardson, J. Biol. Chem., 1992;1994). 이 단백질의 단백질 상호작용을 가능하게 하는 domain은 carboxyl-terminal domain일 것으로 여러 실험에서 대두되었기에, 이 domain의 특성을 파악하기 위해 야생형과 변이체 gene 2.5 단백질들을 각각 GST에 융합한후 fusion 단백질을 정제하였다. 정제된 이 융합 단백질들의 carboxyl-terminal domain이 T7 복제 단백질들과 상호작용을 조사하는지를 조사하기 위해 affinity chromatography로 이용하였다. 실험 결과, 아생형 GST-gene 2.5 융합단잭질(GST-2.5 (WT))는 T7 DNA polymerase 와 상호작용을 하였지만. 변이형 융합단백질(GST-2.5$\Delta$21C)는 interaction을 하지 못했다. 이 결과는 carbohyl-terminal domain이 단백질-단백질 상호작용을 하는데 직접적으로 관여하는 것을 증명하였다. 또한,GST2.5(WT)는 gene 4 protein(helicase/primase)와 직접 상호작용을 하나. GST2.5$\Delta$21C는 상호작용을 하지 못하는 것으로 나타났다. 따라서 gene 4 proteins와의 상호작용에도 gene 2.5 protein의 carboxyl-terminal domain이 직접 관여 한다는 것이 증명되었다. 이상의 결과에서 gene 2.5 protein은 박테리오파지 T7 의 유전자 목제 시 단백질-단백질 상호작용에 관혀아며, 특히 gene 2.5 protein의 carboxyl-terminal domain이 이러한 상호작용에 직접적으로 관여하는 domain이라는 것을 알 수가 있었다.

• Journal of Nutrition and Health
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• 제26권9호
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• pp.1033-1048
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• 1993

This study was designed to describe the effect of the protein quality at different intake level of protein on the protein metabolism in the whole body of growing pigs with a simulation model. Varying to the protein level in feeds, four simulations were conducted. The feed protein level, represented as proportions of digestible protein to the metabolic energy (DP/ME, g/MJ), were 6-8, 11-13, 17-19, and 23-25 DP/ME, respectively. Two protein quality and six weeks of growth time were used at each simulation. The objective function for the simulations was protein deposition in the whole body, which was calculated from the experimental results. The parameters in the simulation were determined by the parameter estimation technique. The results obtained from the simulation were as follows: The protein synthesis and breakdown rates(g/day) in the whole body was increased with the increase of protein quality only at lower or required level of protein intake. They showed a parallel behavior in the course of growth, irrespective of quality and level of feed protein intake. The simulated protein deposition and protein synthesis showed a linear relationship between them at different protein quality and level. The affinity parameter showed a linear relationship between them at different protein quality and level. The affinity parameter showed that arginine, tryptophan and isoleucine were more efficient in the stimulation ofbody protein synthesis. Lysine and phenylalanine+tyrosine were less efficient. The oxidation parameter showed that histidine, pheyalanine+tyrosine were less efficient. The oxidation parameter showed that histidine, phenyalanine+tyrosine, and methionine+cystine were oxidized in larger magnitude than lysine and threonine. The oxidation parameter of most amino acids increased with the increase of protein intake beyond the requirement level, but not any more at highest protein intake level. Finally it was found that the improvement of feed protein quality at the lower or required level of protein intake increase protein deposition through a parallel increase of protein synthesis and breakdown.

• Asian-Australasian Journal of Animal Sciences
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• 제24권9호
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• pp.1274-1281
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• 2011

Dietary protein restriction affects lipid metabolism in rats. This study was performed to determine the effect of a low protein diet on hepatic lipid metabolism and insulin sensitivity in growing male rats. Growing rats were fed either a control 20% protein diet or an 8% low protein diet. Feeding a low protein diet for four weeks from 8 weeks of age induced a fatty liver. Expression of acetyl-CoA carboxylase, a key lipogenic enzyme, was increased in rats fed a low protein diet. Feeding a low protein diet decreased very low density lipoprotein (VLDL) secretion without statistical significance. Feeding a low protein diet down-regulated protein expression of microsomal triglyceride transfer protein, an important enzyme of VLDL secretion. Feeding a low protein diet increased serum adiponectin levels. We performed glucose tolerance test (GTT) and insulin tolerance test (ITT). Both GTT and ITT were increased in protein-restricted growing rats. Our results demonstrate that dietary protein restriction increases insulin sensitivity and that this could be due to low-protein diet-mediated metabolic adaptation. In addition, increased adiponectin levels may influences insulin sensitivity. In conclusion, dietary protein restriction induces a fatty liver. Both increased lipogenesis and decreased VLDL secretion has contributed to this metabolic changes. In addition, insulin resistance was not associated with fatty liver induced by protein restriction.

• Journal of Nutrition and Health
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• 제31권1호
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• pp.5-12
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• 1998

This study was designed to examine how dietary protein levels affect organ growth and protein metabolism in early and normally weaned rats. Early and normally weaned rats separated fro the dam on the 15th and 121st day postpartum, respectively. were fed diets containing three levels of protein : low(10%) , normal (20%),and high(40%) . On the 35th day, the weight and DNA, RNA and protein contents in brain , liver, and kidney were determined to ascertain organ and cellular growth. Furthermore, serum total protein , albumin , $\alpha$-amino N and creatine and urinary urea N, and creatinine were determined in order to ascertain protein metabolism and renal functions. Dietary protein levels were not observed to significantly affect total DNA content, which may represent an index of cell number in the liver, brain and kidney. Fresh weight and protein/DNA ratio, which may represent indices of cell size, significantly increased in proportion to dietary protein in the kidney. As for the early weaned rats , the liver cell size significantly decreased. Dietary protein levels and weaning periods did not affect serum total protein and albumin . However, serum urea-N significantly increased in proportion to dietary protein levels whereas serum $\alpha$-amino N was decreased by early weaning . Nitrogen retention was lower in early weaned rats fed low or high levels of protein than in normally weaned rats. The results demonstrate that low or high levels of dietary protein have less desirable effects on protein metabolism in prematurely weaned rats.

• 한국축산식품학회지
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• 제18권3호
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• pp.209-215
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• 1998

Effects of protein concentration, ionic strength, pH, and temperature range on the heat-induced denaturation of salt soluble protein extracted from spent layer meat were investigated. Viscosity of salt soluble protein heated at 65$^{\circ}C$ for 30 min began to increase sharply above 7 mg/ml of breast protein concentration, and above 21 mg/ml of leg protein concentration, respectively. Both turbidity and viscosity showed the highest value in cooked protein solution with pH 6.0 and 1% NaCl. The turbidity of salt soluble protein started to increase continuously from 40$^{\circ}C$ to 80$^{\circ}C$. The viscosity increased rapidly from 45$^{\circ}C$ to 60$^{\circ}C$ in breast protein, and increased from 50$^{\circ}C$ to 55$^{\circ}C$ in leg protein, respectively, and then kept relatively constant. Breast protein had higher viscosity than leg protein during heat-induced gelation. Therefore, salt soluble protein from spent layer meat was associated with denatured protein (turbidity change) prior to gelation (viscosity change) during heating. Breast protein showed lower thermal transition temperature, and better gel formation than leg protein during heating.

• Journal of Nutrition and Health
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• 제19권1호
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• pp.32-40
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• 1986

The present study conducted to examine the effects of proteins from different sources on Ca excretion in 6 healthy young adult Korean women. The subjects were given meat protein diet for 5 days and soy protein diet for subsequent 5 days. the two diets were similar in protein and Ca contents. Urinary and fecal samples were collected for the last 2 days of each diet period and were analyzed for Ca and P. The results were as following ; 1) Mean daily urinary calcium excretion was 126.5$\pm$22.70mg for meat protein diet and 83.7$\pm$17.19mg for soy protein diet and the difference was significant (P<0.025). 2) Fecal Ca excretion did not show significant difference between two experimental preiod ; 466.9$\pm$73.68 mg of meat portein diet 284.4$\pm$54.96mg for soy protein diet. 3) Three out of six subjects showed negative balance on meat protein diet, but only one showed negative balance on soy protein diet. The averageof the balances on meat protein diet was -65.4 $\pm$68.19 and that of soy protein diet was 155.3$\pm$52.28 ; the difference was significant(P<0.025). 4) Urinary P excretion tended to be higher on meat protein diet but was not significant compared to soy protein diet . Fecal P excretion was significantly higher (P<0.001) on soy protein diet. Overall P balances for meat protein diet and soy protein diet were 219.94 mg and 229.46mg respectively (P<0.05). The above results show that urinary Ca excretion was significantly higher on meat protein diet but fecal excretion did not show significant difference between meat protein diet and soy protein diet. The overall Ca balance was significantly higher on Soy protein diet compared to meat protein diet.

• 한국동물학회지
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• 제33권2호
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• pp.141-151
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• 1990

Raf protein kinases and protein kinase C는 세포질내 serine/threonine-specific protein에 속한다. 그리고 기능적인 구조와 세포내의 분포 양상은 서로 비슷하다. Raf family oncogene를 발현시키는 a-raf와 c-raf protein kinase에 대한 antibodies로써 남생이 대뇌의 raf protein kinase의 분포를 조사하였다. 일반적으로 raf protein kinase는 제한된 지역에서 즉,general pallium,hippocampal formation, pdmordiuin hippocampi,nucleus of lateral olfactory tract, basal amygdaloid nucleus와bed of stria terminalis에 나타났으며, c-raf protein kinase의 면역학적 labeling은 a-raf보다 그 범위가 넓었다. 그렇지만 labeling되는 intensity는 오히려 a-raf보다 낮았다. 그런데 a-raf에서 가장 명확한 좋은 예는 basal amygdaloid nucleus내의 구형모양의 세포인데, 이 세포는 세포질이 매우 강하게 labeling되어 지므로 ring모양과 같이 나타났다. 특히 c-raf는 protein kinase C 가 많이 나타나는 pyramidal 세포나 Purkinje세포에 많이 존재하는 것을 볼 때 protein kinase에 의하여 활성화되는 myc와 서로 상협작용을 유도한다고 제안하는 바이다.

• 한국양식학회지
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• 제12권2호
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• pp.145-153
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• 1999

This study was conducted to determine the protein requirement of ayu (Plecoglossus altivelis). Two replicate groups of fish initially averaging 6.6 g were fed the five isocaloric diets containing different protein level from 29% to 57% in a flow-through freshwater system for 25 days. White fish meal was used as a sole protein source. Weight gain and feed efficiency of fish increased significantly with dietary protein level up to 43% (P＜0.05) with no additional response above this level. Protein and lipid retention, moisture, protein and lipid contents of body were not affected by dietary protein levels (P>0.05). Daily protein intake increased significantly with dietary protein level, whereas protein efficiency ratio of fish fed the 57% dietary protein decreased (P<0.05). The data obtained in this study indicate that a 43% dietary protein level could be recommended for the optimum growth of ayu.

• 식품과학과 산업
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• 제52권1호
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• pp.60-67
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• 2019

Protein is a major nutrient of food and has long been studied for nutritional and utility value. Among them, rice protein is attracting attention because of its hypoallergenic characteristics and nutritional value. Rice proteins are divided into endosperm protein and bran protein depending on their location. The two proteins differ in their nutritional characteristics and applications. The endosperm protein is an insoluble protein and has an advantage of digestion and absorption. Rice bran protein dissolves well in water. Its amino acid value is high enough to be comparable to that of soy protein, and it has strong antioxidant ability. Rice protein is a healthy vegetable protein because of its health and hypoallergenic properties. It has been widely used in children's or patients' food, and recently for muscle supplement and health food. Rice protein is considered to be a very effective and useful material as it has been discovered so far.