Cystine in l-alanyl-l-tyrosine is formed by the connection of two cysteine molecules through a disulfide bond. When the disulfide bond in l-alanyl-l-tyrosine is formed, the sulfhydryl groups (-SH) of two cysteine residues are oxidized, losing two hydrogen atoms and forming a disulfide bond (-S-S-). The formation product is itself because alanyl-L-cystine is a dipeptide composed of alanine and cystine connected by a disulfide bond.
In some specific reaction systems, the disulfide bond may undergo further reactions. For example:
Reduction: Under the action of reducing agents such as β-mercaptoethanol and dithiothreitol (DTT), the disulfide bond is broken, forming two cysteine residues, that is, alanyl-L-cysteine.
Reaction with Other Sulfhydryl-containing Substances: It may undergo an exchange reaction with other sulfhydryl-containing compounds in the system to form new disulfide bond compounds. For example, it can react with another cysteine or a small molecule containing a sulfhydryl group to generate products connected by different disulfide bonds. The specific products depend on the substances participating in the reaction.
