Editing Taurine (section)

===Biosynthesis===
Among the diverse pathways by which natural taurine can be biosynthesized, its pathways in the human liver are from [[cysteine]] and/or [[methionine]].<ref name=RippsShen2012/><ref name = PubChem>{{cite web |title=Taurine |url=https://pubchem.ncbi.nlm.nih.gov/compound/Taurine |publisher=PubChem, US National Library of Medicine|date=25 May 2024|accessdate=31 May 2024}}</ref> With regard to the route from [[cysteine]]: mammalian taurine synthesis occurs in the [[liver]] via the [[cysteine sulfinic acid]] pathway. In this pathway, [[cysteine]] is first oxidized to its sulfinic acid, catalyzed by the enzyme [[cysteine dioxygenase]]. Cysteine sulfinic acid, in turn, is [[Decarboxylation|decarboxylated]] by [[sulfinoalanine decarboxylase]] to form [[hypotaurine]]. Hypotaurine is enzymatically oxidized to yield taurine by [[hypotaurine dehydrogenase]].<ref>{{cite journal | vauthors = Sumizu K | title = Oxidation of hypotaurine in rat liver | journal = Biochimica et Biophysica Acta | volume = 63 | pages = 210–212 | date = September 1962 | pmid = 13979247 | doi = 10.1016/0006-3002(62)90357-8 }}</ref>

Taurine is also produced by the [[transsulfuration pathway]], which converts [[homocysteine]] into [[cystathionine]]. The cystathionine is then converted to [[hypotaurine]] by the sequential action of three enzymes: [[cystathionine gamma-lyase]], [[cysteine dioxygenase]], and cysteine sulfinic acid decarboxylase. Hypotaurine is then oxidized to taurine as described above.<ref>{{cite journal | vauthors = Ripps H, Shen W | title = Review: taurine: a "very essential" amino acid | journal = Molecular Vision | volume = 18 | pages = 2673–2686 | date = 2012 | pmid = 23170060 | pmc = 3501277 }}</ref>

A pathway for taurine biosynthesis from [[serine]] and [[sulfate]] is reported in [[microalgae]],<ref name=McCusker2014/> developing [[chicken]] [[embryo]]s,<ref>{{cite journal | vauthors=Machlin LJ, Pearson PB, Denton CA |title=The Utilization of Sulfate Sulfur for the Synthesis of Taurine in the Developing Chick Embryo |date=1955 |journal=Journal of Biological Chemistry |volume=212 |issue=1 |pages=469–475 |doi=10.1016/s0021-9258(18)71134-4 |pmid=13233249 |issn=0021-9258|doi-access=free }}</ref> and chick [[liver]].<ref>{{cite journal | vauthors=Sass NL, Martin WG |date=1972-03-01 |title=The Synthesis of Taurine from Sulfate III. Further Evidence for the Enzymatic Pathway in Chick Liver |url=http://ebm.sagepub.com/lookup/doi/10.3181/00379727-139-36232 |journal=Experimental Biology and Medicine |language=en |volume=139 |issue=3 |pages=755–761 |doi=10.3181/00379727-139-36232 |pmid=5023763 |s2cid=77903 |issn=1535-3702}}</ref> Serine dehydratase converts serine to [[2-aminoacrylate]], which is converted to [[cysteic acid]] by [[3'-phosphoadenylyl sulfate|3′-phosphoadenylyl sulfate]]:2-aminoacrylate ''C''-[[sulfotransferase]]. Cysteic acid is converted to taurine by cysteine [[sulfinic acid]] [[decarboxylase]].
[[File:Degradation of Cysteine to Taurine.svg|class=skin-invert-image|thumb|center|800px|alt=reaction diagram|Oxidative degradation of cysteine to taurine]]