Technical Information Amino Acids Cysteine

Cysteine

Cysteine, represented by the symbol Cys or C, is an amino acid that is considered semiessential for protein synthesis. The thiol side chain in cysteine plays an active role as a nucleophile in enzymatic reactions. Cysteine exists in nature as a chiral molecule, with only L-cysteine being naturally occurring. The thiol group in cysteine can undergo oxidation, resulting in the formation of cystine, a disulfide derivative that plays a crucial structural role in various proteins. l-Cysteine, primarily the L-enantiomer, serves as a precursor in the food, pharmaceutical, and personal-care industries. One of its significant applications is in the production of flavors. Additionally, l-Cysteine is employed as a processing aid in baking. Cysteine is extensively utilized as a target for site-directed labeling experiments, enabling the investigation of biomolecular structure and dynamics. Maleimides selectively react with cysteine through a covalent Michael addition in site-directed spin labeling for EPR or paramagnetic relaxation-enhanced NMR, further highlighting its importance. The codons UGU and UGC encode cysteine.

Structure
CAS Number 52-90-4
Classification

Polar amino acids, including

Cysteine

Glycine

Glutamine

Threonine

Tyrosine

Serine

Asparagine
Categories
Cysteine Biosynthesis Related Compounds
63-68-3 L-Methionine
29908-03-0 S-Adenosyl-L-methionine
979-92-0 S-Adenosyl-L-homocysteine
S-Ribosyl-L-homocysteine
6027-13-0 L-Homocysteine
56-88-2 L-Cystathionine
52-90-4 L-Cysteine

Cysteine and Derivatives:

Cysteine:

Derivatives: