Editing Threonine (section)

==Metabolism==
Threonine is metabolized in at least three ways:
* In many animals it is converted to [[pyruvate]] via [[threonine dehydrogenase]].  An intermediate in this pathway can undergo [[thiolysis]] with CoA to produce [[acetyl-CoA]] and [[glycine]].
* In humans the gene for threonine dehydrogenase is an inactive [[pseudogene]],<ref>{{Cite book|url=https://books.google.com/books?id=XVNPAQAAQBAJ&pg=PA310|title=Biochemical, Physiological, and Molecular Aspects of Human Nutrition – E-Book|last1=Stipanuk|first1=Martha H.|last2=Caudill|first2=Marie A.|year=2013|publisher=Elsevier Health Sciences|isbn=9780323266956|language=en}}</ref> so threonine is converted to [[α-ketobutyrate]]. The mechanism of the first step is analogous to that catalyzed by [[serine dehydratase]], and the serine and threonine dehydratase reactions are probably catalyzed by the same enzyme.<ref>{{Cite book|url=https://books.google.com/books?id=93yeKr9W9TwC&pg=PA129|title=Biochemistry for Nurses|last1=Bhardwaj|first1=Uma|last2=Bhardwaj|first2=Ravindra|publisher=Pearson Education India|isbn=9788131795286|language=en}}</ref>
* In many organisms it is [[Phosphorylation|O-phosphorylated]] by [[Serine/threonine-specific protein kinase|a kinase]] preparatory to further metabolism. This is especially important in [[bacteria]] as part of the [[biosynthesis of cobalamin]] ([[Vitamin B12]]), as the product is converted to [[1-aminopropan-2-ol|(R)-1-aminopropan-2-ol]] for incorporation into the vitamin's sidechain.<ref name="pmid28137297">{{cite journal |last1=Fang |first1=H |last2=Kang |first2=J |last3=Zhang |first3=D |title=Microbial production of vitamin B<sub>12</sub>: a review and future perspectives. |journal=Microbial Cell Factories |date=30 January 2017 |volume=16 |issue=1 |pages=15 |doi=10.1186/s12934-017-0631-y |pmid=28137297 |pmc=5282855 |doi-access=free }}</ref>
*Threonine is used to synthesize glycine during the endogenous production of L-carnitine in the brain and liver of rats.<ref>{{cite journal |last1=Adeva-Andany |first1=M |last2=Souto-Adeva |first2=G |last3=Ameneiros-Rodríguez |first3=E |last4=Fernández-Fernández |first4=C |last5=Donapetry-García |first5=C |last6=Domínguez-Montero |first6=A |title=Insulin resistance and glycine metabolism in humans. |journal=Amino Acids |date=January 2018 |volume=50 |issue=1 |pages=11–27 |doi=10.1007/s00726-017-2508-0 |pmid=29094215|s2cid=3708658 }}</ref><ref>{{cite journal |last1=Dalangin |first1=R |last2=Kim |first2=A |last3=Campbell |first3=RE |title=The Role of Amino Acids in Neurotransmission and Fluorescent Tools for Their Detection. |journal=International Journal of Molecular Sciences |date=27 August 2020 |volume=21 |issue=17 |page=6197 |doi=10.3390/ijms21176197 |pmid=32867295 |pmc=7503967 |doi-access=free }}</ref>