What is cystine?

Cystine is indeed the oxidized form of cysteine. Cysteine is an amino acid that contains a thiol (-SH) group. When two cysteine molecules undergo oxidation, the thiol groups can form a covalent bond, leading to the formation of cystine, which consists of two cysteine residues connected by a disulfide bond (–S–S–). This disulfide linkage is crucial in protein structure and stability, particularly in extracellular proteins where such bonds contribute to the overall conformation and function of the protein. Cystine plays an important role in the folding of proteins, making it essential in biochemical processes involving protein structure.