white crystals or crystalline powder
DL-Cysteine hydrochloride is used in cell culture. It is also used in photochemical vascular injury (performed using dl-cysteine hydrochloride along with other components). It may be used in the preparation of DL-4-carboxy-3-formyl-2,2,-dimethylthiazolidine.
DL-Cysteine is a racemic mixture of the proteinogenic amino acids L-cysteine and the non-proteinogenic D-cysteine. DL-Cysteine is used as an organic reagent and in comparative physicochemical analysis of processes such as crystallization.
Crystallise the salt from hot 20% HCl and dry it under vacuum over P2O5. It also crystallises from EtOH with m 175o (hydrate). When crystallised from absolute EtOH or EtOH/Et2O, it has m 140-141.5o (anhydrous). [Rurner & Voitle J Am Chem Soc 72 628 1950, Albert Biochem J 50 690 1953, Beilstein 4 IV 3145.]
