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`
`Preparation Instructions
`This product is soluble in water (100 mg/ml), yielding a
`clear, colorless solution.
`
`Storage/Stability
`Stock solutions of cysteine are relatively stable at
`acidic pH, especially in degassed solutions. Aqueous
`solutions of cysteine oxidize readily in air to give
`cystine al neutral or basic pH.7
`
`References
`1. Textbook of Biochemistry with Clinical
`Correlations, Devlin, T . M., ed., Wiley -Liss (New
`York, NY: 1992), p. 33.
`2. Uren, J. R., and Lazarus, H., L-cyst(e)ine
`requirements of malignant cells and progress
`toward depletion therapy. Cancer Treat. Rep.,
`63(6), 1073-1079 (1979).
`3. Parsons, R. B., et al., Toxicity of cysteine and
`cysteine sulphinic acid to human neuronal cell(cid:173)
`lines. J. Neurol. Sci., 152 (Suppl 1 ), S62-66
`(1997).
`4. Parsons, R. B., et al., In vitro effect of the cysteine
`metabolites homocysteic acid, homocysteine and
`cysteic acid upon human neuronal cell lines.
`Neurotoxicology, 19(4-5), 599-603 (1998).
`5. Albers, J. J., et al., Isolation, characterization, and
`assay of lecithin-cholesterol acyltransferase.
`Methods Enzymol., 129, 763-783 (1986).
`6. Molecular Cloning: A Laboratory Manual, 3rd ed.,
`Sambrook, J. and Russell, D. W., CSHL Press
`(Cold Spring Harbor, NY: 2001), pp. 15. 18-15.19.
`7. Data for Biochemical Research, 3rd ed., Dawson,
`R. M. C., et al., Oxford University Press (New
`York, NY: 1986), pp. 12-13.
`
`GCY/NSB 5/06
`
`L-Cysteine hydrochloride monohydrate
`Cell culture tested, meets USP testing specifications
`
`Product Number C6852
`
`Product Description
`Molecular Formula: C3 H7NO2S • HCI • H2O
`Molecular Weight: 175.6
`CAS Number: 7048-04-6
`
`This product is tested for endotoxin levels and
`suitability for cell culture experiments.
`
`Cysteine is a major biological source of sulfur and is
`one of the two common sulfur-containing amino acids.
`The biosynthesis of cysteine occurs through the initial
`condensation of homocysteine and serine via
`cystathionine synthase to form cystathionine, which in
`turn undergoes cleavage by cystathionase to give
`cysteine and a-ketobutyrate. Cysteine can readily
`dimerize to form cystine via the oxidation of the thiol
`side chain residues to give a disulfide covalent bond.
`The formation of such cystine links between cysteine
`residues in proteins is an important part of the
`stabilization of the three-dimensional structure of
`proteins.1
`
`An investigation into cysteine and cystine levels in
`normal and malignant cells with a relationship to
`y-cystathionase levels and tumor sensitivity to
`L-cysteine and cystine depletion has been reported. 2
`The toxicity of human neuronal cell lines to cysteine
`and its metabolites has been investigated. 3
`.4 Cysteine
`can inhibit the activity of enzymes such as lecithin(cid:173)
`cholesterol acyltransferase. 5
`
`A protocol for the use of cysteine in pulse-chase
`experiments to study protein expression from an
`inducible promoter has been reported. 6
`
`Precautions and Disclaimer
`For Laboratory Use Only. Not for drug, household or
`other uses.
`
`Sigma brand products are sold 1hrough Sigma-Aldrich, Inc.
`Sigma-Aldrich, Inc. warran1s tha1 ils producls conform 10 1he informalion contained in 1his and olher Sigma-Aldrich publicalions. Purchaser
`must determine the suitability of the product(s) for their particular use. Additional terms and conditions may apply. Please see reverse side of
`the invoice or packing slip.
`
`Eton Ex. 1079
`1 of 1
`
`