• Nutrition Research and Practice
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• 제3권1호
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• pp.64-71
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• 2009

Amino acids are fundamental nutrients for protein synthesis and cell growth (increase in cell size). Recently, many compelling evidences have shown that the level of amino acids is sensed by extra- or intra-cellular amino acids sensor(s) and regulates protein synthesis/degradation. Mammalian target of rapamycin complex 1 (mTORC1) is placed in a central position in cell growth regulation and dysregulation of mTOR signaling pathway has been implicated in many serious human diseases including cancer, diabetes, and tissue hypertrophy. Although amino acids are the most potent activator of mTORC1, how amino acids activate mTOR signaling pathway is still largely unknown. This is partly because of the diversity of amino acids themselves including structure and metabolism. In this review, current proposed amino acid sensing mechanisms to regulate mTORC1 and the evidences pro/against the proposed models are discussed.

• Preventive Nutrition and Food Science
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• 제3권4호
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• pp.368-373
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• 1998

Plasma amino acid concentration and Urinary exretion of free amino acids were measured in health female vegetarians(n=20, 19.9 $\pm$0.43 years old ) and age-mateched imnivores(n=20, 21.9$\pm$0.38years old) in Korean. differences infasting plasma amino acid concentrations and plasma aminogram pattern were not spectacular between the vegetarian and omnivore controls. Compared to the omnivores, vegetarians showed significantly lower plasma levels of methionine , phenylalanine, $\alpha$-aminobutyrate, citrulline, phosposerine and tarurine, and significantly higher plasma concentrations of arginine, $\alpha$-aminobutyrate, cirtrulline, phosphosierine and taurine, and significantly higher plasma concentrations of arginine, $\alpha$-aminoadipate, asparagine, aspartate, glutamate and ornithine. Although these differences were statistically significant, they were all within the normal range (21~70% differences )for human adults. Most of the urinary amino acids (nmol/mg creatinine or $\mu$mol/24 hr urine) were excreted to significantly lesser degree in vegetarians than was the case in omnivore controls. For almost every individual free amino acid, plasma concentration did not significantly correlate with urinary excretion level. These results indicate that vegetarians excreted less amino acids in their urine than did dominivores, most probably in an effort to maintain amino acid homeostasis to an altered dietary protein intake level and/or amino acid composition of their diets.

• Applied Biological Chemistry
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• 제15권1호
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• pp.35-40
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• 1972

The contents of free amino acids in deembryod brown rice of two varieties were investigated by amino acid autoanalizer in relation to specific gravity grade. The analytical methods of free amino acid were also discussed. 1) The lower the specific gravity of the unhulled rice the higher the content of total free amino acids in the deembryod brown rice, and the similar trend appears to hold on each amino acids. 2) Main free amino acids were serine+asparagine, glutamic acid, aspartic acid, alanine and valine, and maximum values of them were 7.3, 5.1, 4.0, 3.4, 0.9mg/100g rice, respectively. They consist about 85% of total free amino acids in most cases. 3) The contents of soluble nitrogen and free amino acids appear to be lower in high protein variety (IR 667) than in low protein variety (Jinhung). The percentage of free amino acid nitrogen to soluble nitrogen, however, appears to be higher in high protein variety (IR 667). 4) Alanine was much lower than aspartic acid in IR 667 having Indica blood while alanine appears to be higher than aspartic acid in Jinhung (Japonica rice) suggesting varietal difference in amino acid metabolism. 5) Threonine peak was overlaped with glutamine, and serine was with asparagine in this study.

• Journal of Nutrition and Health
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• 제28권10호
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• pp.976-985
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• 1995

Changes in free amino acid concentrations is blood and various tissues were evaluated in cats adapted to the low-protein diet(20% protein, LPD) or the high-protein diet(60% protein, HPD) for 5 weeks. Cumulative body weigth gain for the 5 week period was 463$\pm$43g, and -128$\pm$40g for cats fed HPD and LPD, respectively. Feeding HPD significantly increased the size of liver and kidney. Cats adapted to HPD for 5 weeks have significantly elevated plasma concrntrations of essential amino acids (branched-chain amino acides, threonine, trytophan, phenylalanine and methoionine), whereas plasma levels of non-essential amino acids(alanine, asparagine, glycine, glutamine and serine) were significantly reduced in animals adapted to HPD(p<0.01, or p<0.001) compared to the values for the cats fed LPD. Changes in free amino acid concentratioks in whole blood induced by the variations in dietary level of protein closely reflect the pattern seen in plasma. Amino acids such as branched-chain amino acids, proline and threonine were most difficult to maintain homeostasis and consistantly elevated in lever, kidney, skeletal muscle and brain, as well as in blood of cats adapted to HPD(p<0.01 or p<0.001). All of the free amino acids in jejunum, excluding taurine and ornithine, were significantly elevated in animals adapted to HPD, most probably due to the rapid absorption of large amount of amino acids across the epithelium of small intestine.

• Asian-Australasian Journal of Animal Sciences
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• 제15권1호
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• pp.38-44
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• 2002

Nine crossbred castrated lambs fitted with rumen and duodenum cannula and fed a diet of hay and concentrate formulated with ground corn and soybean meal as main ingredients were used to assess the duodenal ideal amino acid pattern. Three synthetic amino acid mixtures with different profile of essential amino acids were duodenally infused in order to get three different amino acid patterns flowing into the duodenum. The mixtures were designed to have similar amino acid profile as rumen microbial protein (Pm), casein (Pc) and modified muscle amino acid (Pmm). Results showed a lower urine nitrogen excretion (p=0.05), a higher nitrogen retention (p=0.04) and bodyweight gain with treatment Pmm. The modified muscle amino acid pattern also promoted a lower ratio of Gly to other amino acids in plasma (Gly/OAA) and a higher RNA and RNA/DNA concentration in the liver of the sheep. Meanwhile, the urea concentration in plasma was reduced and the insulin concentration was increased with Pmm treatment. No differences in glucose and growth hormone concentration in plasma were found among three treatments. All results obtained indicate that the modified muscle amino acid pattern (Lys 100%, Met+Cys 39%, Thr 76%, His 41%, Arg 72%, Leu 158%, Ile 81%, Val 105%, Phe 81% and Trp 13%) was the best for growing sheep.

• 대한수의학회지
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• 제13권1호
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• pp.17-21
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• 1973

Free amino acid extracts of musculus brachiocephalicus and musculus glutaeus of cattle, swine, goats and rabbits are analyzed to see the composition and the contents of free amino acids by thin layer chromatography and automatic amino acid analyzer. The results obtained are summarized as follows: 1. Meats of cattle, swine, goats and rabbits analyzed by thin layer chromatography have 6 kinds of free amino acids such as glycine, histidine, methionine, lysine, alanine and leucine, and the spots of glycine in chromatogram of meats of cattle, swine and goats and the ones of methionine in chromatogram of meats of rabbits are the largest and the most denes of all other ones. 2. Distribution curves of free amino acids in meats of cattle, swine, goats and rabbits showed significant differences, but differences on distribution curves of free amino acids between musculus-brachiocephalicus and musculus glutaeus of the same tested animal are not significant. 3. Contents of free amino acids in meats of cattle, swine, goats and rabbits showed significant differences, but differences on contents of free amino acids between musculus brachiocephalicus and musculus glutaeus of the same tested animal are not significant.

• The Korean Journal of Physiology and Pharmacology
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• 제18권5호
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• pp.371-376
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• 2014

Amino-acid neurotransmitter system dysfunction plays a major role in the pathophysiology of depression. Several studies have demonstrated the potential of amino acids as a source of neuro-specific biomarkers could be used in future diagnosis of depression. Only partial amino acids such as glycine and asparagine were determined from certain parts of rats' brain included hippocampi and cerebral cortex in previous studies. However, according to systematic biology, amino acids in different area of brain are interacted and interrelated. Hence, the determination of 34 amino acids through entire rats' brain was conducted in this study in order to demonstrate more possibilities for biomarkers of depression by discovering other potential amino acids in more areas of rats' brain. As a result, 4 amino acids (L-aspartic acid, L-glutamine, taurine and ${\gamma}$-amino-n-butyric acid) among 34 were typically identified as potentially primary biomarkers of depression by data statistics. Meanwhile, an antidepressant called Fluoxetine was employed to verify other potential amino acids which were not identified by data statistics. Eventually, we found L-${\alpha}$-amino-adipic acid could also become a new potentially secondary biomarker of depression after drug validation. In conclusion, we suggested that L-aspartic acid, L-glutamine, taurine, ${\gamma}$-amino-n-butyric acid and L-${\alpha}$-amino-adipic acid might become potential biomarkers for future diagnosis of depression and development of antidepressant.

• 한국환경농학회지
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• 제35권2호
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• pp.104-110
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• 2016

BACKGROUND: There is lack of comprehensive compositional data of the amino acid profile of spinach with regard to different cultivars. A more detailed knowledge in this aspect will be of benefit in the future selection of spinach genotypes with improved nutritional quality.METHODS AND RESULTS: The effects of cultivar type (Jeoncheonhu, Sagyejul, Namdongcho and Mustang) and harvest time (79^th, 116^th and 145^th days after sowing or DAS) on the concentrations of free amino acids in field-grown spinach (Spinacia oleracea) were examined. About 35 different free amino acids were detected and quantified by the amino acid analyzer. Glutamic acid and proline were identified as the major amino acids, while α -aminoadipic acid and α-aminobutyric acid were present in much lower concentrations. Spinach constituted 1468.4 mg/100 g total free amino acids (TAA), of which essential amino acids, neutral/acidic amino acids and sulphur containing amino acids constituted around 15, 45 and 2% of the TAA, respectively. The most limiting amino acids among the leafy vegetables - cysteine was recorded only in Mustang harvested at 116 DAS. Free amino acid contents did not differ significantly among the spinach cultivars and also at different harvest times.CONCLUSION: The data show that, either of the spinach cultivars, preferably Mustang harvested on or after 116 DAS can serve as a significant source of nutritionally relevant amino acids to meet the demand of the growing populations.

• 월간포장계
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• 통권300호
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• pp.86-89
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• 2018

• Asian-Australasian Journal of Animal Sciences
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• 제22권8호
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• pp.1186-1194
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• 2009

The objective of this study was to estimate the optimum dietary essential amino acid pattern for male Taiwan country chicks. A series of experiments was conducted with chicks, 14 d of age, for 2 wks. A basal synthetic diet was established using a dose response test for all essential amino acids referring to the broiler requirements recommended by NRC (1994). Twelve chicks were sacrificed at the beginning to provide initial body nitrogen data, and every group of six birds received the basal diet or a diet with a deficiency in a single essential amino acid in twenty one treatments by intubation according to their daily metabolic body weight (MBW). Deposited body nitrogen was determined using comparative slaughtering. According to the daily intake from the limiting amino acid per unit of MBW and the body nitrogen accretion rates for every two deficient groups with the same limiting amino acid but at different levels, a corresponding straight line was computed for each essential amino acid to intersect with a horizontal line made by the body nitrogen accretion rate of the control group. The x coordinate of the intersection represented the daily requirement for growth plus maintenance based on MBW corresponding to the essential amino acid. The amino acid ratios can be considered as the optimum pattern of dietary essential amino acids. The results, expressed with respect to lysine = 100, were arginine 105, methionine 81, histidine 34, tryptophan 18, leucine 103, phenylalanine 135, isoleucine 69, threonine 65 and valine 79. This pattern could be utilized to compute the dietary requirements (g/kg feed) for all essential amino acids by multiplying by the requirement of a single essential amino acid cited from the literature.