L-Cystine EP



Technical Data

CAS Number: 56-89-3
Molecular Formula: [-SCH2CH(NH2)CO2H]2
Molecular Weight: 240.30
Beilstein Registry Number: 1728094
EC Number: 200-296-3

FabriChem Specifications

DescriptionWhite or almost white crystalline powder
I.R. IdentificationComplies with Reference
Specific Optical Rotation at 20° C-218° to -224°
Loss on Drying≤ 0.2 %
State of Solution
(C = 10%, HCl 2N)
Clear and not more intensely colored than reference solution Y7
Sulfated Ash≤ 0.1 %
Heavy Metals≤ 10 ppm
Lead≤ 5 ppm
Iron≤ 10 ppm
Chloride≤ 200 ppm
Sulfate≤ 300 ppm
Ammonium≤ 200 ppm
Other Amino Acids≤ 0.2 %
Assay98.5 to 101.0%
Microbial Analysis
Aerobic Plate Count1,000/g
EnterobacteriaceaeAbsent/1 g
Positive coagulase staphylococciAbsent/1 g
SalmonellaAbsent/100 g
Yeast< 100/g
Mold< 100/g
E. ColiAbsent/1 g

Molecular Structure



L-Cystine has been used to prepare stock solution which in turn is utilized for determining the L-cysteine and L-Cystine in pharmaceutical preparations as well as in urine samples by using spectro-fluorimetric flow injection method.

Cystine is required for the synthesis of glutathione that protects the cells from oxidative stress. A specific x(c)-cysteine/glutamate antiporter mediates cellular uptake of cysteine in exchange for glutamate. Inhibition of cysteine uptake induces toxicity in neuronal cells.