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CAS 52-90-4

CAS 52-90-4 matches 0 EU annex records across Annex II–VI of Regulation 1223/2009.

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Chemical identity and properties

PubChem 2D chemical structure for CAS 52-90-4
CAS 52-90-4PubChem CID 5862

L-(+)-Cysteine

IUPAC name
(2R)-2-amino-3-sulfanylpropanoic acid
Molecular formula
C3H7NO2S
Molecular weight
121.16 g/mol
Exact mass
121.01974964 Da
XLogP3
-2.5
Topological polar surface area
64.3 Ų
Hydrogen-bond donors
3
Hydrogen-bond acceptors
4
Covalent units
1
Defined stereocentres
1

Also known as

L-cysteinecysteineCystein(R)-2-Amino-3-mercaptopropanoic acidThioserineHalf-cystinebeta-MercaptoalanineL-Cystein
16 more reported names
CysteinumL-CyscisteinaHalf cystine2-Amino-3-mercaptopropionic acidL-Alanine, 3-mercapto-FREE CYSTEINECisteinumFEMA No. 3263Cisteinum [Latin]NSC-8746alpha-Amino-beta-thiolpropionic acidL-2-Amino-3-mercaptopropionic acidbeta-Mercaptoalanine, L-(2R)-2-amino-3-mercaptopropanoic acidL Cysteine
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External database identifiers

Retrieved from NIH PubChem on 2026-08-31 by checksum-valid CAS matching. Chemical properties do not replace the regulatory decision on this page.

Records for CAS 52-90-4

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How CAS 52-90-4 is used on this site

CAS 52-90-4 is the Chemical Abstracts Service identifier used to pin this page to a specific substance. In the current dataset, 0 EU annex records share this identifier, which helps you cross-check whether the same substance appears under one regulatory context or several.

Use this page when a supplier specification, SDS or raw-material dossier gives you CAS 52-90-4 and you need to see every linked Annex II–VI record in one place. The entry cards above are the quickest route to concentration limits, warnings, annex placement and product-type conditions.