Registration Dossier
Registration Dossier
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EC number: 200-157-7 | CAS number: 52-89-1
Endpoint summary
Administrative data
Description of key information
Occurance in Nature
L-Cysteine, which is the main component of the substance L-Cysteine hydrochloride (monohydrate), is widely distributed in the biosphere. The substance is synthesised in living organisms as amino acid and incorporated in proteins. Nevertheless L-Cysteine is the rarest "normal" amino acid in proteins.
Environmental fate
The substance L-cysteine hydrochloride (as well as the mono hydrate form) is readily biodegradable.
The substance can be expected to have a low potential for adsorption and bioaccumulation because of its low octanol water partition coefficient.
Due to its ready biodegradation and the acid character the substance is not expected to accumulate in the biosphere and geosphere.
In case of an exposure to the environment the substance is expected to be found in the compartment water. This is due to its good water solubility and non volatile properties.
Based on these properties and the requirements of the REACH regulation no further testing is necessary.
In accordance with article 2(7)(b) and Annex V 6., REACH the hydrate free form of L-Cysteine hydrochloride is registered. L-Cysteine hydrochloride monohydrate (CAS 7048-04-6, hydrate part of the molecule = 10.25 %) is the manufactured and imported substance and was therefore in many cases used for testing.
It is generally accepted that water and especially water of crystallisation has no toxicologically relevant effects. Therefore, the effect levels of L-Cysteine hydrochloride monohydrate can be used to calculate the corresponding dosages of L-Cysteine hydrochloride (anhydrous (free of water of crystallisation)).
Thus, the conclusion on hazard assessment and classification holds true for the anhydrous form as well.
Additional information
Information on Registered Substances comes from registration dossiers which have been assigned a registration number. The assignment of a registration number does however not guarantee that the information in the dossier is correct or that the dossier is compliant with Regulation (EC) No 1907/2006 (the REACH Regulation). This information has not been reviewed or verified by the Agency or any other authority. The content is subject to change without prior notice.
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