制限アミノ酸

WordNet

street name for lysergic acid diethylamide (同)back breaker, battery-acid, dose, dot, Elvis, loony toons, Lucy in the sky with diamonds, pane, superman, window pane, Zen
any of various water-soluble compounds having a sour taste and capable of turning litmus red and reacting with a base to form a salt
having the characteristics of an acid; "an acid reaction"
strictly limiting the reference of a modified word or phrase; "the restrictive clause in `Each made a list of the books that had influenced him limits the books on the list to only those particular ones defined by the clause"
pertaining to or containing any of a group of organic compounds of nitrogen derived from ammonia (同)aminic
the radical -NH2 (同)amino_group

PrepTutorEJDIC

酸性の / 酸味のある,すっぱい(sour) / (言葉・態度などが)厳しい,しんらつな / 酸 / すっぱいもの / 《俗》=LSD
制限する,限定する

Wikipedia preview

出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2013/01/14 18:12:01」(JST)

wiki en

An essential amino acid or indispensable amino acid is an amino acid that cannot be synthesized de novo by the organism (usually referring to humans), and therefore must be supplied in the diet.

Essentiality vs. conditional essentiality in humans

Essential	Nonessential **
Histidine	Alanine
Isoleucine	Arginine*
Leucine	Aspartic acid
Lysine	Cysteine*
Methionine	Glutamic acid
Phenylalanine	Glutamine*
Threonine	Glycine*
Tryptophan	Proline*
Valine	Serine*
	Tyrosine*
	Asparagine*
	Selenocysteine

(*) Essential only in certain cases.^[1]^[2]

(**) Pyrrolysine, sometimes considered "the 22nd amino acid", is not listed here as it is not used by humans. ^[3]

The amino acids regarded as essential for humans are phenylalanine, valine, threonine, tryptophan, isoleucine, methionine, leucine, lysine, and histidine.^[4] Additionally, cysteine (or sulphur-containing amino acids), tyrosine (or aromatic amino acids), and arginine are required by infants and growing children.^[5]^[6] Essential amino acids are "essential" not because they are more important to life than the others, but because the body does not synthesize them. They must be present in the diet or they will not be present in the body. In addition, the amino acids arginine, cysteine, glycine, glutamine, histidine, proline, serine and tyrosine are considered conditionally essential, meaning they are not normally required in the diet, but must be supplied exogenously to specific populations that do not synthesize them in adequate amounts.^[1]^[2] An example would be with the disease phenylketonuria (PKU). Individuals living with PKU must keep their intake of phenylalanine extremely low to prevent mental retardation and other metabolic complications. However, they cannot synthesize tyrosine from phenylalanine, so tyrosine becomes essential in the diet of PKU patients.

The distinction between essential and non-essential amino acids is somewhat unclear, as some amino acids can be produced from others. The sulfur-containing amino acids, methionine and homocysteine, can be converted into each other but neither can be synthesized de novo in humans. Likewise, cysteine can be made from homocysteine but cannot be synthesized on its own. So, for convenience, sulfur-containing amino acids are sometimes considered a single pool of nutritionally-equivalent amino acids as are the aromatic amino acid pair, phenylalanine and tyrosine. Likewise arginine, ornithine, and citrulline, which are interconvertible by the urea cycle, are considered a single group.

Recommended daily amounts

Estimating the daily requirement for the indispensable amino acids has proven to be difficult; these numbers have undergone considerable revision over the last 20 years. The following table lists the WHO recommended daily amounts currently in use for essential amino acids in adult humans, together with their standard one-letter abbreviations.^[6]

Amino acid(s)	mg per kg body weight	mg per 70 kg	mg per 100 kg
H Histidine	10	700	1000
I Isoleucine	20	1400	2000
L Leucine	39	2730	3900
K Lysine	30	2100	3000
M Methionine + C Cysteine	10.4 + 4.1 (15 total)	1050	1500
F Phenylalanine + Y Tyrosine	25 (total)	1750	2500
T Threonine	15	1050	1500
W Tryptophan	4	280	400
V Valine	26	1820	2600

The recommended daily intakes for children aged three years and older is 10% to 20% higher than adult levels and those for infants can be as much as 150% higher in the first year of life.

Use of essential amino acids

At the level of the ribosome, the cells of eukaryotes require up to 21 different amino acids for protein synthesis. A shortfall of any one of these amino acids would thus be a limiting factor in protein synthesis. However, eukaryotes can synthesize some of these amino acids from other substrates. Consequently, only a subset of the amino acids used in protein synthesis are essential nutrients. Whether a particular amino acid is essential depends upon the species and the stage of development.

Scientists had known since the early 20th century that rats could not survive on a diet whose only protein source was zein, which comes from maize (corn), but recovered if they were fed casein from cow's milk. This led William Cumming Rose to the discovery of the essential amino acid threonine.^[7] Through manipulation of rodent diets, Rose was able to show that ten amino acids are essential for rats: lysine, tryptophan, histidine, phenylalanine, leucine, isoleucine, methionine, valine, and arginine, in addition to threonine. Rose's later work showed that eight amino acids are essential for adult human beings, with histidine also being essential for infants. Longer term studies established histidine is also essential for adult humans.^[8]

Because of the obvious difference in the nutritional value of zein versus casein in rat nutrition, various attempts have been made to express the "quality" or "value" of various kinds of protein. Measures include the biological value, net protein utilization, protein digestibility-corrected amino acid score. These concepts are important in the livestock industry, because the relative lack of one or more of the essential amino acids in animal feeds would have a limiting effect on growth and thus on feed conversion ratio. Thus, various feedstuffs may be fed in combination to increase net protein utilization, or a supplement of an individual amino acid (methionine, lysine, threonine, or tryptophan) can be added to the feed.

Although proteins from plant sources tend to have a relatively low biological value, in comparison to protein from eggs or milk, they are nevertheless "complete" in that they contain at least trace amounts of all of the amino acids that are essential in human nutrition.^[9] Eating various plant foods in combination can provide a protein of higher biological value.^[10] Certain native combinations of foods, such as corn and beans, soybeans and rice, or red beans and rice, contain the essential amino acids necessary for humans.^[11]

Essential amino acid deficiency

The amino acids that are essential in the human diet were established in a series of experiments led by William Cumming Rose. The experiments involved elemental diets to healthy male graduate students. These diets consisted of cornstarch, sucrose, butterfat without protein, corn oil, inorganic salts, the known vitamins, a large brown "candy" made of liver extract flavored with peppermint oil (to supply any unknown vitamins), and mixtures of highly purified individual amino acids. The main outcome measure was nitrogen balance. Rose noted that the symptoms of nervousness, exhaustion, and dizziness were encountered to a greater or lesser extent whenever human subjects were deprived of an essential amino acid.^[12]

Essential amino acid deficiency should be distinguished from protein-energy malnutrition, which can manifest as marasmus or kwashiorkor. Kwashiorkor was once attributed to pure protein deficiency in individuals who were consuming enough calories ("sugar baby syndrome"). However, this theory has been challenged by the finding that there is no difference in the diets of children developing marasmus as opposed to kwashiorkor.^[13]

Mnemonics

Using the one-letter designation shown above, mnemonic devices have been developed for use in memorizing the essential amino acids. Previous devices have utilized the first letter of the amino acids' names, and in general did not include arginine which is not always essential. Mnemonic devices in common use are PVT TIM HaLL^[14] and TT HALL V(ery) IMP(ortant).^[15]

Alternative mnemonics based on the amino acids' assigned single letters include LIFT HIM KIW(V)I and TV FILM HW(R)K. Such mnemonics are preferable, since they avoid confusion between amino acids sharing the same first letter (Alanine, Arginine, Aspartic Acid and Asparagine, for example - only one of which, arginine, is a (conditionally) essential amino acid). Similar confusion arises between Thr, Tyr and Trp - only one of which (Tyr) is nonessential.

Another method uses the first letter of each essential amino acid to begin each word in a phrase, such as: "Any Help In Learning These Little Molecules Proves Truly Valuable."^[16] This method begins with the two amino acids that need some qualifications as to their requirements.w Also, There was [a] fat man [that] hated vanilla icing, [but] loved Kit-Kats.

A useful mnemonic sentence using the single-letter code is: The Whole Food Larder Really Must Have Various Key Ingredients.

A medical student may find the following way useful as it distinguishes the glucogenic essential amino acids from the ketogenic essential amino acids:

Gluconeogenic (Val, His, Thr, Met) : "Val and His Three Methods"

Gluconeogenic/Ketogenic (Ile, Trp, Phe) : "Illy Trpped BOTH Pheasants"

Ketogenic (Leu, Lys) : "Ketones in lieu of lysine"

References

^ ^a ^b Fürst P, Stehle P (1 June 2004). "What are the essential elements needed for the determination of amino acid requirements in humans?". Journal of Nutrition 134 (6 Suppl): 1558S–1565S. PMID 15173430. http://jn.nutrition.org/cgi/content/full/134/6/1558S.
^ ^a ^b Reeds PJ (1 July 2000). "Dispensable and indispensable amino acids for humans". J. Nutr. 130 (7): 1835S–40S. PMID 10867060. http://jn.nutrition.org/cgi/content/full/130/7/1835S.
^ Richard Cammack. "Newsletter 2009, Biochemical Nomenclature Committee of IUPAC and NC-IUBMB". http://www.chem.qmul.ac.uk/iubmb/newsletter/2009.html#item3.
^ Young VR (1994). "Adult amino acid requirements: the case for a major revision in current recommendations". J. Nutr. 124 (8 Suppl): 1517S–1523S. PMID 8064412. http://jn.nutrition.org/cgi/reprint/124/8_Suppl/1517S.pdf.
^ Imura K, Okada A (1998). "Amino acid metabolism in pediatric patients". Nutrition 14 (1): 143–8. doi:10.1016/S0899-9007(97)00230-X. PMID 9437700.
^ ^a ^b FAO/WHO/UNU (2007). "PROTEIN AND AMINO ACID REQUIREMENTS IN HUMAN NUTRITION". WHO Press. http://whqlibdoc.who.int/trs/WHO_TRS_935_eng.pdf., page 150
^ Rose WC, Haines WJ, Warner DT, Johnson JE. The amino acid requirements of man. II. The role of threonine and histidine. J Biol Chem. 1951;188(1):49-58
^ J D Kopple and M E Swendseid (May 1975). "Evidence that histidine is an essential amino acid in normal and chronically uremic man.". J Clin Invest. 55 (5): 881–891. doi:10.1172/JCI108016. PMC 301830. PMID 1123426. http://www.jci.org/articles/view/108016.
^ McDougall J. Plant foods have a complete amino acid composition. Circulation. 2002;105(25):e197
^ Woolf, P. J.; Fu, L. L.; Basu, A. (2011). Haslam, Niall James. ed. "VProtein: Identifying Optimal Amino Acid Complements from Plant-Based Foods". PLoS ONE 6 (4): e18836. doi:10.1371/journal.pone.0018836. PMC 3081312. PMID 21526128. //www.ncbi.nlm.nih.gov/pmc/articles/PMC3081312/. edit
^ http://hyperphysics.phy-astr.gsu.edu/hbase/organic/essam.html "Tillery points out that a number of popular ethnic foods involve such a combination, so that in a single dish, one might hope to get the ten essential amino acids. Mexican corn and beans, Japanese rice and soybeans, and Cajun red beans and rice are examples of such fortuitous combinations."
^ Rose, WC; Haines, WJ; Warner, DT (1951), "The amino acid requirements of man. III. The role of isoleucine; additional evidence concerning histidine." (PDF), J Biol Chem 193 (2): 605-612, http://www.jbc.org/content/193/2/605.full.pdf, retrieved 15 Dec 2012
^ Ahmed T, Rahman S, Cravioto A. Oedematous malnutrition. Indian J Med Res. 2009;130(5):651-654
^ Mnemonic at medicalmnemonics.com 442 128
^ ;MATT VIL PLy Essential amino acids Essential amino acids, Mnemonic.
^ Williams, R.A.D.; Eliot, J.C. (1989). Basic and Applied Dental Biochemistry. Elsevier Health Sciences. pp. 149. ISBN 0-443-03144-4.

External links

Amino acid content of some vegetarian foods - In a meal, make sure at least one food has a low value in each row of the "Amount to meet RDA" column, at veganhealth.org
Amino Acid Profiles of Some Common Feeds at Virginia Tech
Molecular Expressions: The Amino Acid Collection - Has detailed information and crystal photographs of each amino acid. at Florida State University
vProtein - An online software tool to analyze the essential amino acid profiles of single and pairs of plant based foods based on human requirements.

UpToDate Contents

全文を閲覧するには購読必要です。 To read the full text you will need to subscribe.

1. フェニルケトン尿症の概要 overview of phenylketonuria
2. 先天性代謝異常：個々の障害の発見 inborn errors of metabolism identifying the specific disorder
3. 乳児および小児における低血糖症の原因 causes of hypoglycemia in infants and children
4. 尿素サイクル障害：臨床的特徴および診断 urea cycle disorders clinical features and diagnosis
5. 乳児における腸管不全関連肝疾患 intestinal failure associated liver disease in infants

English Journal

Current issues in dietary acrylamide: formation, mitigation and risk assessment.

Pedreschi F, Mariotti MS, Granby K.Author information Departamento de Ingeniería Química y Bioprocesos, Pontificia Universidad Católica de Chile, Santiago, Chile; ASIS-UC Interdisciplinary Research Program on Tasty and Healthy Foods, Pontificia Universidad Catoĺica de Chile, Santiago, Chile.AbstractAcrylamide (AA) is known as a neurotoxin in humans and it is classified as a probable human carcinogen by the International Agency of Research on Cancer. AA is produced as by-product of the Maillard reaction in starchy foods processed at high temperatures (>120 °C). This review includes the investigation of AA precursors, mechanisms of AA formation and AA mitigation technologies in potato, cereal and coffee products. Additionally, most relevant issues of AA risk assessment are discussed. New technologies tested from laboratory to industrial scale face, as a major challenge, the reduction of AA content of browned food, while still maintaining its attractive organoleptic properties. Reducing sugars such as glucose and fructose are the major contributors to AA in potato-based products. On the other hand, the limiting substrate of AA formation in cereals and coffee is the free amino acid asparagine. For some products the addition of glycine or asparaginase reduces AA formation during baking. Since, for potatoes, the limiting substrate is reducing sugars, increases in sugar content in potatoes during storage then introduce some difficulties and potentially quite large variations in the AA content of the final product. Sugars in potatoes may be reduced by blanching. Levels of AA in different foods show large variations and no general upper limit is easily applicable, since some formation will always occur. Current policy is that practical measures should be taken voluntarily to reduce AA formation in vulnerable foods since AA is considered a health risk at the concentrations found in foods.
Journal of the science of food and agriculture.J Sci Food Agric.2014 Jan 15;94(1):9-20. doi: 10.1002/jsfa.6349. Epub 2013 Sep 15.
Acrylamide (AA) is known as a neurotoxin in humans and it is classified as a probable human carcinogen by the International Agency of Research on Cancer. AA is produced as by-product of the Maillard reaction in starchy foods processed at high temperatures (>120 °C). This review includes the inve
PMID 23939985

Immune changes and neurotransmitters: Possible interactions in depression?

Sperner-Unterweger B, Kohl C, Fuchs D.Author information Clinic for Biological Psychiatry, Department of Psychiatry and Psychotherapy, Innsbruck Medical University, Anichstr.35, 6020 Innsbruck, Austria. Electronic address: barbara.sperner-unterweger@i-med.ac.at.AbstractA disturbed metabolism of catecholamines and other neurotransmitters appears to play a major role in the pathogenesis of neurospychiatric symptoms, such as changes in mood and depression. This symptomatology is common in patients with chronic inflammatory disorders such as infections, autoimmune diseases, or cancer. The pathogenesis of these symptoms is still unclear. Pro-inflammatory stimuli interfere not only with the neural circuits and neurotransmitters of the serotonergic system but also with those of the adrenergic system. The pro-inflammatory cytokine interferon-γ stimulates the biosynthesis of 5,6,7,8-tetrahydrobiopterin (BH4), which is a co-factor for several aromatic amino acid mono-oxygenases and is rate-limiting for the biosynthesis of the neurotransmitter serotonin and the catecholamines dopamine, epinephrine (adrenaline) and norepinephrine (noradrenaline). Interferon-γ triggers the high output of reactive oxygen species in macrophages, which can destroy the oxidation-labile BH4. Recent data suggests that oxidative loss of BH4 in chronic inflammatory conditions can reduce the biosynthesis of catecholamines, which may relate to disturbed adrenergic neurotransmitter pathways in patients.
Progress in neuro-psychopharmacology & biological psychiatry.Prog Neuropsychopharmacol Biol Psychiatry.2014 Jan 3;48:268-76. doi: 10.1016/j.pnpbp.2012.10.006. Epub 2012 Oct 17.
A disturbed metabolism of catecholamines and other neurotransmitters appears to play a major role in the pathogenesis of neurospychiatric symptoms, such as changes in mood and depression. This symptomatology is common in patients with chronic inflammatory disorders such as infections, autoimmune dis
PMID 23085509

GTP Dysregulation in Bacillus subtilis Cells Lacking (p)ppGpp Results in Phenotypic Amino Acid Auxotrophy and Failure To Adapt to Nutrient Downshift and Regulate Biosynthesis Genes.

Kriel A, Brinsmade SR, Tse JL, Tehranchi AK, Bittner AN, Sonenshein AL, Wang JD.Author information Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas, USA.AbstractThe nucleotide (p)ppGpp inhibits GTP biosynthesis in the Gram-positive bacterium Bacillus subtilis. Here we examined how this regulation allows cells to grow in the absence of amino acids. We showed that B. subtilis cells lacking (p)ppGpp, due to either deletions or point mutations in all three (p)ppGpp synthetase genes, yjbM, ywaC, and relA, strongly require supplementation of leucine, isoleucine, valine, methionine, and threonine and modestly require three additional amino acids. This polyauxotrophy is rescued by reducing GTP levels. Reduction of GTP levels activates transcription of genes responsible for the biosynthesis of the five strongly required amino acids by inactivating the transcription factor CodY, which represses the ybgE, ilvD, ilvBHC-leuABCD, ilvA, ywaA, and hom-thrCB operons, and by a CodY-independent activation of transcription of the ilvA, ywaA, hom-thrCB, and metE operons. Interestingly, providing the eight required amino acids does not allow for colony formation of (p)ppGpp(0) cells when transitioning from amino acid-replete medium to amino acid-limiting medium, and we found that this is due to an additional role that (p)ppGpp plays in protecting cells during nutrient downshifts. We conclude that (p)ppGpp allows adaptation to amino acid limitation by a combined effect of preventing death during metabolic transitions and sustaining growth by activating amino acid biosynthesis. This ability of (p)ppGpp to integrate a general stress response with a targeted reprogramming of gene regulation allows appropriate adaptation and is likely conserved among diverse bacteria.
Journal of bacteriology.J Bacteriol.2014 Jan;196(1):189-201. doi: 10.1128/JB.00918-13. Epub 2013 Oct 25.
The nucleotide (p)ppGpp inhibits GTP biosynthesis in the Gram-positive bacterium Bacillus subtilis. Here we examined how this regulation allows cells to grow in the absence of amino acids. We showed that B. subtilis cells lacking (p)ppGpp, due to either deletions or point mutations in all three (p)p
PMID 24163341