グルコース・アラニン回路
WordNet
- pass through a cycle; "This machine automatically cycles"
- an interval during which a recurring sequence of events occurs; "the never-ending cycle of the seasons" (同)rhythm, round
- recur in repeating sequences
- a single complete execution of a periodically repeated phenomenon; "a year constitutes a cycle of the seasons" (同)oscillation
- a periodically repeated sequence of events; "a cycle of reprisal and retaliation"
- a series of poems or songs on the same theme; "Schuberts song cycles"
- cause to go through a recurring sequence; "cycle the laundry in this washing program"
- a monosaccharide sugar that has several forms; an important source of physiological energy
- the sport of traveling on a bicycle or motorcycle
- a crystalline amino acid that occurs in many proteins
PrepTutorEJDIC
- 『周期』,循環期;一巡り / 周波,サイクル / (英雄・伝説などを扱った)一連の詩(物語) / 『自転車』;三輪車;オートバイ / 自転車に乗る / 循環する,反復する
- ブドウ糖
- 自転車に乗ること,サイクリング
Wikipedia preview
出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2016/01/19 16:38:26」(JST)
[Wiki en表示]
The Cahill cycle, also known as the alanine cycle or glucose-alanine cycle, is the series of reactions in which amino groups and carbons from muscle are transported to the liver.[1] It is quite similar to the Cori cycle in the cycling of nutrients between skeletal muscle and the liver. When muscles degrade amino acids for energy needs, the resulting nitrogen is transaminated to pyruvate to form alanine. This alanine is shuttled to the liver where the nitrogen enters the urea cycle and the pyruvate is used to make glucose.[2]
The Cahill cycle is less productive than the Cori cycle, which uses lactate, since a byproduct of energy production from alanine is production of urea.[3] Removal of the urea is energy-dependent, requiring four "high-energy" phosphate bonds (3 ATP hydrolyzed to 2 ADP and one AMP), thus the net ATP produced is less than that found in the Cori cycle. However, unlike in the Cori cycle, NADH is conserved because lactate is not formed. This allows for it to be oxidized via the electron transport chain. This pathway requires the presence of alanine aminotransferase, which is restricted to tissues such as muscle, liver, and the intestine. Therefore, this pathway is used instead of the Cori cycle only when an aminotransferase is present and when there is a need to transfer ammonia to the liver.
The alanine cycle also serves other purposes:
- Recycles carbon skeletons between muscle and liver
- Transports ammonium to the liver and is converted into urea.
References
- ^ Naik, Pankaja (1 November 2011). Essentials of Biochemistry. JP Medical Ltd. p. 168. ISBN 9789350254912.
- ^ Kaplan Medical USMLE Step 1 Qbook. Kaplan Publishing. 2 September 2008. p. 172. ISBN 9781419553158.
As muscle proteins are catabolized, the amino acid skeletons are used as fuel in the muscle, while the amino groups are transaminated from pyruvate, forming alanine, which is then transported to the liver and kidney cortex to be used in gluconeogenesis (Cahill cycle).
- ^ Cifuentes, Alejandro (5 February 2013). Foodomics: Advanced Mass Spectrometry in Modern Food Science and Nutrition. John Wiley & Sons. p. 335. ISBN 9781118537350.
Alanine plays an important role in the Cahill cycle or alanine-glucose cycle, and changes in alanine metabolite may indicate that this cycle could be modified (Yan et al., 2009).
External links
- Diagram at Colorado.edu
- [1] at indstate.edu
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Metabolism: carbohydrate metabolism: glycolysis/gluconeogenesis enzymes
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| Glycolysis |
- Hexokinase (HK1, HK2, HK3, Glucokinase)→/Glucose 6-phosphatase←
- Glucose isomerase
- Phosphofructokinase 1 (Liver, Muscle, Platelet)→/Fructose 1,6-bisphosphatase←
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- Fructose-bisphosphate aldolase (Aldolase A, B, C)
- Triosephosphate isomerase
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- Glyceraldehyde 3-phosphate dehydrogenase
- Phosphoglycerate kinase
- Phosphoglycerate mutase
- Enolase
- Pyruvate kinase (PKLR, PKM2)
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| Gluconeogenesis only |
| to oxaloacetate: |
- Pyruvate carboxylase
- Phosphoenolpyruvate carboxykinase
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| from lactate (Cori cycle): |
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| from alanine (Alanine cycle): |
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| from glycerol: |
- Glycerol kinase
- Glycerol dehydrogenase
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| Regulatory |
- Fructose 6-P,2-kinase:fructose 2,6-bisphosphatase
- PFKFB1, PFKFB2, PFKFB3, PFKFB4
- Bisphosphoglycerate mutase
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Index of inborn errors of metabolism
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| Description |
- Metabolism
- Enzymes and pathways: citric acid cycle
- pentose phosphate
- glycoproteins
- glycosaminoglycans
- phospholipid
- cholesterol and steroid
- sphingolipids
- eicosanoids
- amino acid
- urea cycle
- nucleotide
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| Disorders |
- Citric acid cycle and electron transport chain
- Glycoprotein
- Proteoglycan
- Fatty-acid
- Phospholipid
- Cholesterol and steroid
- Eicosanoid
- Amino acid
- Purine-pyrimidine
- Heme metabolism
- Symptoms and signs
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| Treatment |
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Index of nutrition
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| Description |
- Vitamins
- Cofactors
- Metal metabolism
- Fats
- metabolism
- intermediates
- lipoproteins
- Sugars
- Glycolysis
- Glycogenesis and glycogenolysis
- Fructose and galactose
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| Disease |
- Vitamins
- Carbohydrate
- Lipid
- Metals
- Other
- Symptoms and signs
- Tests
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| Treatment |
- Drugs
- Vitamins
- Mineral supplements
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UpToDate Contents
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English Journal
- Metabolomic strategy for the detection of metabolic effects of spermine supplementation in weaned rats.
- Liu G1, Fang T, Yan T, Jia G, Zhao H, Huang Z, Chen X, Wang J, Xue B.
- Journal of agricultural and food chemistry.J Agric Food Chem.2014 Sep 10;62(36):9035-42. doi: 10.1021/jf500882t. Epub 2014 Sep 2.
- The purpose of this study is to examine the effects of spermine supplementation on weaned rat metabolism. A metabolomic strategy employing high-resolution (1)H NMR spectroscopy and multivariate data analysis was used to investigate rat biological responses to spermine ingestion. Rats received intrag
- PMID 25162370
- Impaired amino acid metabolism contributes to fasting-induced hypoglycemia in fatty acid oxidation defects.
- Houten SM1, Herrema H, Te Brinke H, Denis S, Ruiter JP, van Dijk TH, Argmann CA, Ottenhoff R, Müller M, Groen AK, Kuipers F, Reijngoud DJ, Wanders RJ.
- Human molecular genetics.Hum Mol Genet.2013 Dec 20;22(25):5249-61. doi: 10.1093/hmg/ddt382. Epub 2013 Aug 9.
- The importance of mitochondrial fatty acid β-oxidation (FAO) as a glucose-sparing process is illustrated by patients with inherited defects in FAO, who may present with life-threatening fasting-induced hypoketotic hypoglycemia. It is unknown why peripheral glucose demand outpaces hepatic gluconeoge
- PMID 23933733
Japanese Journal
- 侵襲時用高濃度分岐鎖アミノ酸含有成分栄養剤の開発と有用性 : 特に術後早期経腸栄養における効果について
- 東 博
- 北里医学 22(6), 583-596, 1992-12-31
- … これはglucose alanine cycleの基質としてBCAAが酸化し,糖新生を初めとする糖代謝においても効果的に作用することを示唆するものと言える。 …
- NAID 110004696533
Related Links
- 栄養・生化学辞典 グルコース-アラニンサイクルの用語解説 - 骨格筋から放出されるアラニンが肝臓で糖新生経路でグルコースとなって骨格筋にもどり，再びアラニンへと代謝される循環の現象．
- Simply stated, this cycle involves muscle protein being degraded to provide more glucose to generate additional ATP for muscle contraction. Alanine plays a key role in glucose-alanine cycle between tissues and liver. In muscle and ...
★リンクテーブル★
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- 英
- glucose-alanine cycle
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[★]
- 英
- glucose-alanine cycle
- 関
- アラニン回路
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アラニン
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- A、Ala、alanyl、L-alanine
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