Cistein: Razlika med redakcijama
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Vrstica 1:
{{distinguish|citozin|cistin|citizin|citidin|Sistin}}
{{redirect|Cys}}
{{chembox
| Verifiedfields = changed
| Watchedfields = changed
| verifiedrevid = 443554430
| Name = <small>L</small>-cistin
| ImageFile_Ref = {{chemboximage|correct|??}}
| ImageFile = L-Cystein - L-Cysteine.svg
| ImageFileL1 = L-cysteine-3D-balls2.png
| ImageFileR1 = L-cysteine-3D-vdW2.png
| IUPACName = Cysteine
| OtherNames = 2-Amino-3-sulfhidrilpropanojska kislina
|Section1={{Chembox Identifiers
| IUPHAR_ligand = 4782
| UNII_Ref = {{fdacite|changed|FDA}}
| UNII = K848JZ4886
| ChEMBL_Ref = {{ebicite|correct|EBI}}
| ChEMBL = 54943
| InChI = 1/C3H7NO2S/c4-2(1-7)3(5)6/h2,7H,1,4H2,(H,5,6)/t2-/m0/s1
| InChIKey = XUJNEKJLAYXESH-REOHCLBHBU
| InChI1 = 1/C3H7NO2S/c4-2(1-7)3(5)6/h2,7H,1,4H2,(H,5,6)
| InChIKey1 = XUJNEKJLAYXESH-UHFFFAOYAC
| SMILES1 = C(C(C(=O)O)N)S
| StdInChI_Ref = {{stdinchicite|correct|chemspider}}
| StdInChI = 1S/C3H7NO2S/c4-2(1-7)3(5)6/h2,7H,1,4H2,(H,5,6)
| StdInChIKey_Ref = {{stdinchicite|correct|chemspider}}
| StdInChIKey = XUJNEKJLAYXESH-UHFFFAOYSA-N
| CASNo = 52-90-4
| CASNo_Ref = {{cascite|correct|CAS}}
| CASNo2_Ref = {{cascite|changed|??}}
| CASNo2 = 52-89-1
| CASNo2_Comment = (hydrochloride) <!-- also verified at CAS Common Chemistry -->
| EC_number = 200-158-2
| PubChem = 5862
| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}
| ChemSpiderID = 574
| ChemSpiderID_Comment = (Racemic)
| ChemSpiderID1_Ref = {{chemspidercite|correct|chemspider}}
| ChemSpiderID1 = 5653
| ChemSpiderID1_Comment = (L-form)
| KEGG_Ref = {{keggcite|correct|kegg}}
| KEGG = D00026
| ChEBI_Ref = {{ebicite|correct|EBI}}
| ChEBI = 15356
| SMILES = C([C@@H](C(=O)O)N)S
}}
|Section2={{Chembox Properties
| Properties_ref = <ref>{{RubberBible62nd|page=C-259}}.</ref>
| C=3 | H=7 | N=1 | O=2 | S=1
| Appearance = white crystals or powder
| Density =
| MeltingPtC = 240
| MeltingPt_notes = decomposes
| SpecRotation = +9.4° (H<sub>2</sub>O, ''c'' = 1.3)
| Solubility = soluble
| SolubleOther = 1.5g/100g etanol 19 oC <ref>{{Cite book | url = https://books.google.com/?id=xteiARU46SQC&pg=PA15 | title = Food Chemistry | isbn = 9783540699330 | author1 = Belitz | first1 = H.-D | last2 = Grosch | first2 = Werner | last3 = Schieberle | first3 = Peter | date = 2009-02-27 | postscript = <!-- Bot inserted parameter. Either remove it; or change its value to "." for the cite to end in a ".", as necessary. -->{{inconsistent citations}}
}}</ref>
}}
}}
'''Cistein''' (okrajšano '''Cys''' ali '''C''')<ref>{{cite web | author=IUPAC-IUBMB Joint Commission on Biochemical Nomenclature | title=Nomenclature and Symbolism for Amino Acids and Peptides | work=Recommendations on Organic & Biochemical Nomenclature, Symbols & Terminology etc | url=http://www.chem.qmul.ac.uk/iupac/AminoAcid/ | accessdate=17. 5. 2007}}</ref> je α-[[aminokislina]] s kemijsko formulo HO<sub>2</sub>CCH(NH<sub>2</sub>)CH<sub>2</sub>SH. Spada med neesencialne aminokisline, kar pomeni, da poteka sinteza v človeškem telesu. Zapisujeta jo [[kodon]]a UGU in UGC. Stranska veriga cisteina je [[tiol]], ki je nepolarne narave, in molekulo s tem uvršča med hidrofobne aminokisline. Tiolna skupina pogosto sodeluje v encimskih reakcijah kot [[nukleofil]]. Poleg tega je ta skupina dovzetna tudi za [[oksidacija|oksidacijo]], pri čemer iz dveh cisteinov nastane disulfidni derivat [[cistin]], ki igra pomembno strukturno vlogo v mnogih proteinih. Cistein je ime dobil ravno iz cistina.
Vrstica 56 ⟶ 118:
=== ''N-acetilcistein (NAC)'' ===
N-acetil-L-cistein (NAC) je derivat cisteina, pri katerem je na dušikov atom pritrjena acetilna skupina. Spojina se prodaja kot prehransko dopolnilo z antioksidativnimi lastnosti, prav tako ščiti jetra. NAC se pogosto uporablja kot zdravilo proti kašlju, saj s cepitvijo disulfidnih vezi utekočini sluz in olajša izkašljevanje. Prav tako pri bolnikih s cistično fibrozo, s cepitvijo disulfidnih vezi tanjša abnormalno debelo plast sluzi. NAC se uporablja tudi kot specifičen protistrup v primeru prevelikega odmerka acetaminofena (paracetamol).
== Viri ==
{{opombe}}
{{Aminokisline}}
[[Kategorija:Aminokisline]]
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