Registration Dossier

Registration Dossier

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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.

The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.

Diss Factsheets

Administrative data

Link to relevant study record(s)

Description of key information

L-cysteine is a macronutrient, normally present in proteins both as cysteine and as cystine. In the human body, L-cysteine is the central compound in sulfur metabolism. It is degraded to pyruvate by a process two-phase, desulfurization and transamination. Cysteine can also be metabolized to form taurine and anhydride carbonate according to the cysteinsulfinate pathway, in which the initial step involves the oxidation of cysteine to cysteine sulfonate.

This step is catalyzed by cysteine dioxigenase. Subsequently, the sulphonated cysteine can be decarboxylated to form taurine or it can be metabolized to pyruvate and sulfite, via the intermediate betasulphonylpyruvate, and finally to carbon dioxide and sulphate.

Key value for chemical safety assessment

Additional information

Bibliographic source:

ECHA Registration Dossier: L-cysteine.