• 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.

• The Korean Journal of Food And Nutrition
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• v.20 no.2
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• pp.158-163
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• 2007

The compositions of tofus made with Baktae and Huktae were compared to those made with other respective types of soybeans. The lipid and protein contents of Baktae were 20.8% and 39.7%, while those of Huktae were 15.8% and 41.1%, respectively. In both soybean types, linoleic acid(18:2), oleic acid(18:1), and palmitic acid(16:0) accounted for more than 80% of the total fatty acids. The tofu made from Baktae was whiter than the tofu made from Huktae, as exhibited by a higher Hunter's L-value. The lipid content of the Baktae tofu(4.41%) was higher than that of the Huktae tofu(3.26%). The amino acid compositions of the Huktae and Baktae tofus were similar, with glutamic acid and aspartic acid being the most abundant amino acids in both tofus. However, the content of the limiting amino acid, methionine, increased 2.5-fold in the tofus as compared to the soybeans, on a per gram protein basis. Isoflavones were lost during tofu making as contents for the tofu were 20${\sim}$25% of those for the soybeans.

• Journal of the Korean Society of Food Science and Nutrition
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• v.26 no.2
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• pp.229-235
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• 1997

The chemical components of 5 domestic wheats(Kru, Suwon 257, Eunpa, Chokwang and Tapdong), Australian standard white wheat(ASW) and dark northern spring wheat(DNS) were determined in terms of amino acids, sugars and minerals for whole wheat and white wheat flour of 70% milling yield. The protein content of whole Eunpa and Tapdong was approximately 15%, and reduced its content approximately 1% after milling compared to that of whole wheats. The high levels of glutamic acid and proline were observed in domestic wheats. The limiting amino acid of domestic wheat was higher than that of ASW, but lower than that of DNS. Especially, Suwon 257 and Tapdong exhibited the higher limiting amino acid content than other domestic wheats. Glutamic acid and proline content increased, while lysine and threonine was decreased after milling. In general, whole wheat exhibited the higher levels of arabinose and xylose, and the lower level of glucose than flour. The results also showed domestic wheat contained the higher amount of arabinose and xylose than the foreign wheats. Domestic wheat and flour possessed the higher amount of mineral such as P, K, Na and Ca than ASW and DNS, while Al and Si were similar to others.

• Journal of Animal Science and Technology
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• v.62 no.4
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• pp.485-494
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• 2020

Limiting amino acids (AAs) for milk production in dairy cows fed on a concentrate diet of corn grain and soybean meal was evaluated in this study. Four lactating and multiparous Holstein cows (in third or fourth parities, with an average body weight of 633 ± 49.2 kg), 8 to 9 weeks into their lactation period, were used in a 4 × 4 Latin square design. The experiment comprised four dietary treatments: (1) no intravenous infusion (control); (2) control plus intravenous infusion of an AA mixture of 6 g/d methionine, 19.1 g/d lysine, 13.8 g/d isoleucine, and 15.4 g/d valine (4AA); (3) control plus intravenous infusion of the AA mixture without methionine (no-Met); and (4) control plus intravenous infusion of the AA mixture without lysine (no-Lys). All animals were fed on a controlled diet (1 kg/d alfalfa hay, 10 kg/d silage, 14 kg/d concentrate mixture, ad libitum timothy hay). The AA composition of the diet and blood were determined using an automatic AA analyzer. Milk composition (protein, fat, lactose, urea nitrogen, and somatic cell counts) was determined using a MilkoScan. The results showed that feed intake for milk production did not differ from that of intravenous infusion using a limiting AA mixture. The 4AA treatment numerically had the highest milk yield (32.4 kg/d), although there was no difference when compared with the control (31.2 kg/d), no-Met (31.3 kg/d), and no-Lys (31.7 kg/d) treatments. The concentration of AAs in blood plasma of cows in all treatments, mainly isoleucine and valine, increased significantly compared with that of control. The no-Met treatment increased (p < 0.05) the concentration of lysine in the blood relative to the control and no-Lys treatments, whereas the no-Lys treatment increased (p < 0.05) the concentration of methionine relative to the control and no-Met treatments. In conclusion, milk production increased when feeding 10 g/d methionine to the cows, together with their concentrate diet of corn grain and soybean meal.

• Journal of Plant Biotechnology
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• v.40 no.1
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• pp.1-8
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• 2013

Potato is the 4th important crop along with rice, wheat and maize. It contains high quality of starch with relatively high content of vitamin C and protein. However, there is a nutritionally limiting factor due to a low level of sulphur-containing essential amino acid including methionine and cysteine. Recently, recombinant DNA technology and metabolic engineering with genes involved in the bio-synthetic pathway have been applied to enhance the level of these essential amino acids. In this report, it has been discussed about the current status and bottleneck on the development of transgenic potato containing high level of sulphur-containing essential amino acids.

• Asian-Australasian Journal of Animal Sciences
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• v.28 no.4
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• pp.485-493
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• 2015

This study evaluated the in situ ruminal degradability, and subsequent small intestinal digestibility (SID) of dry matter, crude protein (CP), and amino acids (AA) of cottonseed meal (CSM), sunflower seed meal (SFSM) and distillers dried grains with solubles (DDGS) by using the modified three-step in vitro procedure. The ruminal degradability and subsequent SID of AA in rumen-undegradable protein (RUP-AA) varied among three protein supplements. The result show that the effective degradability of DM for SFSM, CSM, and DDGS was 60.8%, 56.4%, and 41.0% and their ruminal fermentable organic matter was 60.0%, 55.9%, and 39.9%, respectively. The ruminal degradable protein (RDP) content in CP for SFSM, CSM, and DDGS was 68.3%, 39.0%, and 32.9%, respectively, at the ruminal solid passage rate of 1.84%/h. The SFSM is a good source of RDP for rumen micro-organisms; however, the SID of RUP of SFSM was lower. The DDGS and CSM are good sources of RUP for lambs to digest in the small intestine to complement ruminal microbial AA of growing lambs. Individual RUP-AA from each protein source was selectively removed by the rumen microorganisms, especially for Trp, Arg, His, and Lys (p<0.01). The SID of individual RUP-AA was different within specific RUP origin (p<0.01). Limiting amino acid was Leu for RUP of CSM and Lys for both RUP of SFSM and DDGS, respectively. Therefore, different protein supplements with specific limitations should be selected and combined carefully in growing lambs ration to optimize AA balance.

• Asian-Australasian Journal of Animal Sciences
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• v.18 no.3
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• pp.358-363
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• 2005

Five crossbred beef cattle (Simmental${\times}$yellow cattle, Shantung Province) fitted with permanent cannulae in the rumen and T-type cannulae at the proximal duodenum and terminal ileum, were fed five different diets containing corn, cotton meal or soybean meal and ammoniated straw to determine the dry matter, crude protein and amino acid flows in duodenal and ileum digesta, and to calculate the regression equations between theoretical and experimental concentration of AA in duodenal digesta. The results showed that there was a strong correlation between experimental (g/d, y) and theoretical CP flows (g/d, x) at the proximal duodenum, the $R^2$-value regression equation of crude protein is very high (0.9636). The $R^2$-value regression equation of the limiting amino acid (such as Met or Lys) is high (0.7573 or 0.9252 respectively). This results indicated that we can formulate better diets fed to beef cattle according to the theoretical amino acid concentration. A mathematical model has been successfully constructed for predicting the supply of absorbed amino acids at the proximal duodenum in growing beef cattle.

• Korean Journal of Food Science and Technology
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• v.12 no.4
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• pp.263-271
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• 1980

Detoxified and deallergenized castor bean protein isolate was prepared from defatted castor bean pomace for use in animal feedstuffs and human foods. Succinylation and acetylation of the ${\varepsilon}-amino$ groups of the protein improved markedly the water solubility of the protein at $pH\;7{\sim}8$. The results of the amino acid analysis of the protein isolate revealed that the sulfur-containing amino acids and L-lysine were limiting amino acids and that succinylation and acetylation caused some little loss of the amino acid content. The L-methionine enriched plastein was synthesized from the protein isolate or the acylated protein isolates and DL-methionine ethyl ester by one step process with papain. By this method the extent of incorporation of L-methionine was about 50%. Pepsin hydrolyzed both unmodified and modified protein isolates at the same rate (about 92%). Tryptic hydrolysis, however, was less for the succinylated protein isolates (about 42%) and less for the acetylated protein isolates (about 26%). The protein efficiency ratio of L-methionine enriched protein isolate (about 2.5 weight %) was 90% that of reference casein. The protein efficiency ratio values of succinylated (88%) and acetylated (84%) protein isolate were 55 and 69% of reference casein, respectively.

• Korean Journal of Food Science and Technology
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• v.19 no.4
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• pp.290-294
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• 1987

The chemical composition of pearled, cutted and pressed barleys showed that there were no significant differences in calorie and proximate composition between pearled and pressed barley. Cutted barley had lower contents in protein, fat and ash but the same calorie value compared with other barleys. The average ratios of calcium to phophorus and essential amino acid to total nitrogen were 0.143 and 1.66, respectively. The amino acid score was the highest in cutted barley followed by pressed barley. The first limiting amino acid for pearled and cutted barley was lysine. while that for pressed barley being threonine. The major fatty acids were linoleic, palmitic and oleic acids, which comprised of about 92% of the total fatty acids. The ratio of polyunsaturated to saturated fatty acid was lower in pressed barley.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.33 no.s01
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• pp.64-85
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• 1988

Peanut seeds are characterized by high oils and proteins with good quality, and are utilized as an edible oil source and a protein-rich food products. The end products, being peanut butter, salted seed, confections, roasting stock and other by-products are favored in world-wide because of their unique roasted peanut flavor. As with many other foods, interest in the composition and chemistry of peanut is largely a result of thier use as human food. Thus, a more complete knowledge of thier chemical and food quality and flavor properties is desired. Literatures are reviewed mainly focucing on the physicochemical properties and nutritional quality of oil, protein and flavor in peanuts. Chemical properties of protein and oil, and volatile flavor component in peanut seeds are studied extensively in view point of chemical and food nutritional value. But in crop base, the synthesis and genetic studies of the chemicals could not provide valuable informations on the breeding for quality improvement. Some essential amino acids are limiting in peanut seeds and the tocopherols are very important in oil stability and for dietary adequacy ratio in high linoleic acid peanut oil, but it is thought to be quite difficult to improve by breeding technique as their lack information of gene actions. However, the selections of high protein and oil, and some essential amino acids and linoleic acid rich genotypes could be helpful for the quality improving. Research studies are also needed to elucidate the relationships between flavor components and consumer perception of peanut flavor.