Cystathionine
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IUPAC name S-((R)-2-amino-2-carboxyethyl)-L-homocysteine | |
Other names L-Cystathionine; S-[(2R)-2-Amino-2-carboxyethyl]-L-homocysteine | |
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ECHA InfoCard | 100.000.269 |
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MeSH | Cystathionine |
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InChI
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Properties | |
Chemical formula | C7H14N2O4S |
Molar mass | 222.26 g·mol−1 |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). N verify (what is YN ?) Infobox references |
Cystathionine is an intermediate in the synthesis of cysteine from homocysteine. It is produced by the transsulfuration pathway and is converted into cysteine by cystathionine gamma-lyase (CTH).
Biosynthetically, cystathionine is generated from homocysteine and serine by cystathionine beta synthase (upper reaction in the diagram below). It is then cleaved into cysteine and α-ketobutyrate by cystathionine gamma-lyase (lower reaction).
An excess of cystathionine in the urine is called cystathioninuria.
Cysteine dioxygenase (CDO), and sulfinoalanine decarboxylase can turn cysteine into hypotaurine and then taurine.[1] Alternately, the cysteine from the cystathionine gamma-lyase can be used by the enzymes glutamate–cysteine ligase (GCL) and glutathione synthetase (GSS) to produce glutathione.
References
- ^ Harris Ripps, Wen Shen (2012). "Review: Taurine: A "very essential" amino acid". Molecular Vision. 18: 2673–2686. PMC 3501277. PMID 23170060.
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lysine→ | |
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leucine→ | |
tryptophan→alanine→ |
G→pyruvate→ citrate |
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G→glutamate→ α-ketoglutarate |
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G→propionyl-CoA→ succinyl-CoA |
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G→fumarate |
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G→oxaloacetate |
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Cysteine metabolism |
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