Editing Alanine (section)

==Physiological function==
===Glucose–alanine cycle===
In mammals, alanine plays a key role in [[glucose–alanine cycle]] between tissues and liver. In muscle and other tissues that degrade amino acids for fuel, amino groups are collected in the form of [[Glutamic acid|glutamate]] by [[transamination]]. Glutamate can then transfer its amino group to [[pyruvate]], a product of muscle [[glycolysis]], through the action of [[alanine aminotransferase]], forming alanine and [[α-ketoglutarate]]. The alanine enters the bloodstream, and is transported to the liver. The alanine aminotransferase reaction takes place in reverse in the liver, where the regenerated pyruvate is used in [[gluconeogenesis]], forming glucose which returns to the muscles through the circulation system. Glutamate in the liver enters [[mitochondria]] and is broken down by [[glutamate dehydrogenase]] into α-ketoglutarate and [[ammonium ion|ammonium]], which in turn participates in the [[urea cycle]] to form [[urea]] which is excreted through the kidneys.<ref name="Lehninger">{{Lehninger4th|pages=684–85|name-list-style=vanc}}.</ref>

The glucose–alanine cycle enables pyruvate and glutamate to be removed from muscle and safely transported to the liver. Once there, pyruvate is used to regenerate glucose, after which the glucose returns to muscle to be metabolized for energy: this moves the energetic burden of gluconeogenesis to the liver instead of the muscle, and all available [[Adenosine triphosphate|ATP]] in the muscle can be devoted to muscle contraction.<ref name="Lehninger"/> It is a catabolic pathway, and relies upon protein breakdown in the muscle tissue. Whether and to what extent it occurs in non-mammals is unclear.<ref>{{Cite book|url=https://books.google.com/books?id=P42VIrgYpKoC&pg=PA23|title=Fish Physiology: Nitrogen Excretion|date=2001-09-07|publisher=Academic Press|isbn=978-0-08-049751-8 |pages=23|language=en}}</ref><ref>{{Cite book|url=https://books.google.com/books?id=H5d2k2b1cWQC&pg=PA172 |title=Nitrogen Metabolism and Excretion| vauthors = Walsh PJ, Wright PA |date=1995-08-31|publisher=CRC Press|isbn=978-0-8493-8411-0 |language=en}}</ref>

===Link to diabetes===
Alterations in the alanine cycle that increase the levels of serum [[alanine aminotransferase]] (ALT) are linked to the development of type II diabetes.<ref>{{cite journal | vauthors = Sattar N, Scherbakova O, Ford I, O'Reilly DS, Stanley A, Forrest E, Macfarlane PW, Packard CJ, Cobbe SM, Shepherd J | display-authors = 6 | title = Elevated Alanine Aminotransferase Predicts New-Onset Type 2 Diabetes Independently of Classical Risk Factors, Metabolic Syndrome, and C-Reactive Protein in the West of Scotland Coronary Prevention Study | journal = Diabetes | volume = 53 | issue = 11 | pages = 2855–60 | date = November 2004 | pmid = 15504965 | doi = 10.2337/diabetes.53.11.2855 | doi-access = free }}</ref>