• Journal of the Korea Institute of Information and Communication Engineering
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• v.22 no.1
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• pp.26-32
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• 2018

The protein secondary structures are important information for studying the evolution, structure and function of proteins. Recently, deep learning methods have been actively applied to predict the secondary structure of proteins using only protein sequence information. In these methods, widely used input features are protein profiles transformed from protein sequences. In this paper, to obtain an effective protein profiles, protein profiles were constructed using protein sequence search methods such as PSI-BLAST and HHblits. We adjust the similarity threshold for determining the homologous protein sequence used in constructing the protein profile and the number of iterations of the profile construction using the homologous sequence information. We used the protein profiles as inputs to convolutional neural networks and recurrent neural networks to predict the secondary structures. The protein profile that was created by adding evolutionary information only once was effective.

• Applied Biological Chemistry
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• v.20 no.1
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• pp.156-170
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• 1977

Some of the recent developments and studies in the area of rice protein are reviewed. Protein content and amino acid composition of rice are briefly described. Emphasis is given to characterization of rice protein fractions, effects of protein content on grain properties and lysine content of rice, occurence of protein in rice grain and biosynthesis of protein during grain development.

• Korean Journal of Poultry Science
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• v.42 no.1
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• pp.87-100
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• 2015

It is well known that dietary protein affects the growth performance and carcass composition of poultry. Over the last several decades, numerous studies have been carried out to investigate to optimize the level of dietary protein since the protein is an important and expensive constituent in poultry feed. It is generally accepted that dietary protein should represent a balance of amino acids supporting the requirements for growth and maintenance of birds. A protein with balanced essential amino acids that matches a bird's requirement and sufficient non-essential amino acid nitrogen to enable the synthesis of all of the non-essential amino acids, is referred to as an 'ideal protein'. Feeding of excess protein or amino acids may result in an amount of nitrogen emission. Most common method to reduce nitrogen emission is using diet formulation which has lower dietary crude protein level and higher concentration of amino acid supplements. However, there are conflicting reports whether low protein diets supplemented with synthetic amino acids can obtain the growth performance equal to high protein diets. Excessive nitrogen excretion caused by amino acid imbalance also may influence the environment of poultry house due to ammonia production from uric acid. These environmental conditions may increase the incidence of skin problem or respiratory diseases of chickens. Various strategies based on comprehensive understanding should be tested to optimize nitrogen utilization and reduce nitrogen emission while maintaining the performance in poultry production.

• Journal of Periodontal and Implant Science
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• v.32 no.2
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• pp.351-360
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• 2002

In the study presented here, identification, purification, and partial characterization of a hemin-regulated protein in Prevotella nigrescens were carried out. The results of this study confirm that the availability of hemin influences the expression of a selected membrane protein as well as the growth rate of P. nigrescens ATCC 33563. The 50 kDa cell envelope associated protein, whose expression is hemin regulated, is considered to be a putative hemin-binding protein from P. nigrescens. Disulfide bonds were not present in this protein, and N'-terminal amino acid sequence analysis revealed that this protein belongs to a new, so far undescribed protein. The 50 kDa protein was found to be rich in hydrophilic amino acids, with glycine comprising approximately 60% of the total amino acids. The study described here is the first to identify, purify, and biochemically characterize a putative hemin-binding protein from P. nigrescens. Work is in progress to further characterize the molecular structure of this protein.

• Asian-Australasian Journal of Animal Sciences
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• v.9 no.1
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• pp.107-111
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• 1996

Studies on the effects of protein levels on the total sulphur amino acid (TSAA) requirements of chickens were conducted on the starter broilers by feeding four levels of crude protein(16, 18, 20 and 23%) at three levels of TSAA (0.83, 0.93 and 1.03%) and on the grower broilers by feeding three levels of crude protein (16, 18 and 20%) at three levels of TSAA(0.72, 0.79 and 0.86%). The metabolisable energy of the diets was maintained constant at 3,200 kcal/kg and the experiments were carried out for two growing periods: starter (0-3 wk) and grower (3-6 wk). The results showed that there were significant differences in body weight gain, feed intake and feed:gain ratio under different protein levels of the starters. Crude protein, ME and TSAA intake were significantly affected by increasing the CP levels. The TSAA requirement of the starter broilers is recommended at 0.93% and it is not influenced by different protein levels used in the experiment. For the grower period, body weight gain and feed:gain ratio improved significantly at higher protein diets. Birds fed higher protein diet consumed greater quantities of protein. Responses to TSAA supplementation for body weight gain, feed intake and feed:gain ratio were not significant. The present results showed that the TSAA level of 0.79 to 0.86% was required for grower diets and that the protein levels of the diet did not influence the TSAA requirement.

• Journal of Nutrition and Health
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• v.30 no.3
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• pp.266-276
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• 1997

To investigate the effects of dietary protein and calcium levels on calcium and bone metabolism Sprague-Dawley male growing rats weighting approximately 91.4g were divided into four groups and fed one of the following four experimental diets-15% protein 0.2% calcium ; 15% protein 0.5% calcium ; 30% protein 0.2% calcium ; 30% protein 0.5% calcium-for five weeks. Calcium intake and excretion, apparent calcium absorption were measured and bone densities and mineral contents of femur and scapula were analyzed. Calcium excretion through feces and urine was significantly greater in animals receiving diets of higher calcium. Fecal calcium but not urinary calcium excretion was greater when the protein level was increased from 15% to 30%. Apparent calcium absorption rate was significantly higher with lower calcium intakes. Serum alkaline phosphatase activity was significantly higher in 0.2% calcium group than in 0.5% calcium group, while urinary hydroxyproline excretion was essentially same among all experimental groups. Weights and mineral contents or protein. Bone weights were greater, but calcium and ash contents of femur and scapula were lower in animals on the diet containing low calcium and high protein, which suggests that bone metabolism may be affected by the interaction between calcium and protein intake. These results indicate that during growth high protein intake might be beneficial to bone health if the diet is sufficient in calcium, however, if the diet fails to provide an optimum amount of calcium, such practice might be detrimental.

• Journal of Nutrition and Health
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• v.22 no.6
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• pp.516-530
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• 1989

A 44-day metabolic study was conducted to compare the effects of soy protein and meat protein on N, Ca, P, and Mg metabolism in young Korean males. Meat protein diet(MPD) and soy protin diet(SPD) were provided for 3 weeks each. For MPD, meat protein Supplied 50.3% of total protein and mean daily suplies of Ca, P, and Mg were 33.28mg, 1013.01mg, 226.81mg respectively. For SPD, soy protein supplied 51.8% of total protein and mean contents of Ca, P and Mg were 737.86mg, 1261.76mg, and 451.3mg. Mean daily fecal and urinary excretions of Ca were 350.6mg and 113.3mg for MPD and 515.0mg and 118.3mg for SPD. Apparent absorption rates in MPD and SPD were 4.2mg in MPD and 700.4mg and 475.1mg SPD. Apparent absorption rates were 65.6% in MPD and 44.5% in SPD(p<0.01). For Mg, fecal and urinary excretions were 144.8mg and 81.2mg in MPD and 292.4mg and 65.5mg in SPD. Apparent absorption rates were 37.5% in MPD and 35.2% in SPD. The correlations between urinary Ca, P, and their balance were significant (p<0.001) in MPD, but not in SPD. Urinary Ca was significantly correlated with urinary N, P, Mg(p<0.001) in MPD, but not in SPD. From these results, meat protein seems to increase the excretions of major minerals compared to soy protein.

• Journal of the Korean Society of Food Science and Nutrition
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• v.26 no.5
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• pp.936-942
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• 1997

The present study was carried out to investigate the effects of dietary protein and magnesium levels on calcium and magnesium metabolism in male Sprague-Dawley rats. Forty-eight male rats(average weight, 210g) divided into six diet groups; protein 8% and Mg-free diet, protein 8% and Mg 400mg/kg diet, protein 8% and Mg 900mg/kg diet, protein 20% and Mg-free diet, protein 20% nd Mg 400mg/kg diet, and protein 20% and Mg 800mg/kg diet group. After the rats were fed with experimental diets concentration were examined. Kidney weight was significantly higher in protein 8% and Mg-free group compared with other groups. Serum calcium concentration of protein8% group tended to decrease with the increase of the level of magnesium. Serum magnesium concentration in protein 8% and 20% group was lower in Mg-free group than that in other groups(p<0.05) and it also increased as the dietary magnesium level was increased. Urinary calcium and magnesium concentration in Mg-free group were significantly lower than those of other groups.

• Archives of Pharmacal Research
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• v.25 no.5
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• pp.572-584
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• 2002

Rapid development in molecular biology and recent advancement in recombinant technology increase identification and commercialization of potential protein drugs. Traditional forms of administrations for the peptide and protein drugs often rely on their parenteral injection, since the bioavailability of these therapeutic agents is poor when administered nonparenterally. Tremendous efforts by numerous investigators in the world have been put to improve protein formulations and as a result, a few successful formulations have been developed including sustained-release human growth hormone. For a promising protein delivery technology, efficacy and safety are the first requirement to meet. However, these systems still require periodic injection and increase the incidence of patient compliance. The development of an oral dosage form that improves the absorption of peptide and especially protein drugs is the most desirable formulation but one of the greatest challenges in the pharmaceutical field. The major barriers to developing oral formulations for peptides and proteins are metabolic enzymes and impermeable mucosal tissues in the intestine. Furthermore, chemical and conformational instability of protein drugs is not a small issue in protein pharmaceuticals. Conventional pharmaceutical approaches to address these barriers, which have been successful with traditional organic drug molecules, have not been effective for peptide and protein formulations. It is likely that effective oral formulations for peptides and proteins will remain highly compound specific. A number of innovative oral drug delivery approaches have been recently developed, including the drug entrapment within small vesicles or their passage through the intestinal paracellular pathway. This review provides a summary of the novel approaches currently in progress in the protein oral delivery followed by factors affecting protein oral absorption.

• Bulletin of the Korean Chemical Society
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• v.23 no.12
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• pp.1724-1728
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• 2002

The adsorption of proteins on the surface of glass slides is essential for the construction of protein chips. Here, we report that a Histidine (His)-tagged protein protein has been efficiently adsorbed on glass coated with nickel. A variety of nickel chloride-coated plates were prepared by the spin-coating method and adsorbed to the His-tagged protein. When the protein was adsorbed onto the surface of a variety of nickel chloride-coated glass slides, the efficiency of protein adsorption was dependent upon the coating conditions such as nickel chloride concentration, the spin speed and the drying temperature. The slides appropriate for protein adsorption were obtained when the slides were coated with 11%(w/w) of $NiCl_2$ at the spin speed of 4000 rpm for 20 sec and then dried at higher than 40°C. The physical properties of their nickel chloride thin layer were characterized by scanning electron microscopy. x-ray diffraction and atomic force microscopy, finding that the nickel chloride particles were around 10 nm in diameter and uniformly crystallized at 101 faces. These results show that nickel chloride-coated slides prepared by the spin-coating method are utilizable for the construction of Histagged protein chips.