• Journal of Sericultural and Entomological Science
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• v.4
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• pp.85-95
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• 1965

This report is to observe the amino acid composition at silk fibroins among varieties by using paper chromatography method and to study how they may concern with the genetical problem and the biochemical synthesis of the fibroin in silkgland. The results reached are as follows: 1. The amino acid composition of silk fibroin among varieties were observed as similar with each other on the paper chromatogram pictures. 2. In spite of the results of the amino acid composition analysis was similar with other workers results, there was some difference among varieties in numerical analysis. 3. The amino acid composition was considered to concern somewhat with the genetic problem of silkworm. 4. Some nutritive amino acids are considered to related with the worm growth more than the silk fibroin. 5. The paper chromatography of this report showed an unknown amino acid which was not found before in specific species silk fibroin and it is imagined as Hydroxyproline in view of other worker's graphy result. 6. The biochemical synthesis mechanism of silk fibroin in the silk gland, neither Stepwise process nor Template, could stand with the results of this paper satisfactory one side.

• Asian-Australasian Journal of Animal Sciences
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• v.19 no.7
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• pp.1040-1046
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• 2006

Studies were carried out with a repeated $4{\times}4$ Latin square design with eight cannulated pigs fed four experimental diets to investigate the effect of dietary fiber and starch sources on apparent ileal and fecal amino acid digestibility. Each period lasted 15 d, with diet acclimation from d 1 to 7, feces collection for 48 h on d 8 to 9 and ileal sample collection for 12 h on d 13 to 15. The four experimental diets consisted mainly of cooked rice with the addition of protein sources (CON), partial replacement of cooked rice with either potato starch (PS), sugar beet pulp (SBP) or wheat bran (WB). Chromic oxide was used as an indigestible marker. With the exception of histidine, lysine and tryptophan, no differences were observed in the apparent ileal digestibility of amino acids between diets. The inclusion of potato starch did not affect the ileal and fecal amino acid digestibility. In comparison with diet CON, a decreased (p<0.05) ileal digestibility of histidine was found in pigs fed diet SBP, while the ileal digestibilities of histidine, lysine and tryptophan were decreased (p<0.05) by the inclusion of wheat bran. Inclusion of fiber sources (sugar beet pulp and wheat bran) caused a reduction (p<0.05) in the fecal amino acid digestibility and the net disappearance of amino acids in the large intestine. Of the indispensable amino acids, there was a 'net synthesis' for methionine in the large intestine of pigs when diets were supplemented with dietary fiber. The decrease in fecal amino acid digestibility with the addition of dietary fiber indicates an increase in the synthesis of bacterial protein in the large intestine.

• Proceedings of the Zoological Society Korea Conference
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• 1995.10b
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• pp.82-82
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• 1995

Regulation of enzyme synthesis by transcriptional and translational control systems provides rather stable adaptation to change of amino acid level in the growth medium, while manipulation of enzyme activity through endproduct feedback inhibition represents rather short-term and reversible ways of adjusting metabolic fluctuation of amino acid level. Various control mechanisms interplay to regulate genes encoding enzymes for amino acid biosynthesis in the yeast, Sacchromyces cerevisiae. When amino acids are in short supply, genes under a cross-pathway regulatory mechanism Or general amino acid control (general control) increase their action, in which Gcn4p is the major positive regulator of gene expression. When cells are cultured in minimal medium, basal level expression is also regulated by supplementary control elements, where inorganic phosphate level is additionally involved. Most of amino acid biosynthetic genes are also regulated by the level of endproduct of the pathway. This pathway-specific regulatory mechanism is called specific amino acid control (specific controD, under which gene expression is reduced when endproduct is present in the medium. Derepression of a gene through general control can be usually overridden by repression through specific control, where the endproduct level of that particular pathway is high and not limiting. In this presentation, regulatory factors for basal level expression and general control of yeast amino acid biosynthesis will be discussed, m addition to pathway-specific repression patterns and interaction between CrOSS- and specific-control mechanisms. Preliminary results are also presented from the investigation of the cloned genes in the threonine biosynthetic pathway of the yeast. yeast.

• Archives of Pharmacal Research
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• v.14 no.4
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• pp.342-345
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• 1991

Synthesis of series of 3-benzalphthalidyl-amino acids and their corresponding methyl esters, dipeptides and tripeptide methyl esters 2a-7c is decribed. All 3-benzalphthalidynamino acids 2a-g were found to possess a remarkable antimicrobial properties against a number of microorganisms and fungi.

• Bulletin of the Korean Chemical Society
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• v.22 no.6
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• pp.551-552
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• 2001

• Journal of the Korean Chemical Society
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• v.39 no.2
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• pp.123-126
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• 1995

• 한국생물공학회:학술대회논문집
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• 2000.11a
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• pp.597-600
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• 2000

In this study the enzymatic synthesis of ester-linked conjugates of amino acid and monosaccharide in pyridine was tested by the catalysis of Optimase M-440, an alkaline serine pretense. Optimase M-440 showed the higher activity in the reaction of monosaccharides which have one or more primary -OH groups. And also Optimase M-440 showed high regioselectivity; The transesterification of primary -OH group selectively occurred.

• Journal of Microbiology and Biotechnology
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• v.9 no.5
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• pp.646-649
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• 1999

A thermophilic bacterium producing D-stereospecific dipeptidase was isolated from Korean soil samples. The enzyme hydrolyzed the peptide bond between D-alanyl-D-alanine (D-Ala-D-Ala). The isolated bacterial strain was rod shaped, gram-positive, motile, and formed an endospore. Morphological and physiological characteristics suggested this microorganism a thermophilic Bacillus species, and was named as Bacillus sp. BCS-l. The production of D-stereospecific dipeptidase was growth-associated and optimal at $55^{\circ}C$. The enzyme was applied for the synthesis of D-amino acid-containing peptide, N-benzyloxycarbonyl-L-aspartyl-D-alanine benzyl ester (Z-L-Asp-D-AlaOBzl), as a model reaction. A thermodynamically controlled synthesis of Z-L-Asp-D-AlaOBzl was achieved in an organic solvent.

• 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 the Korean Chemical Society
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• v.53 no.6
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• pp.631-634
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• 2009