Oxytocine is a mammalian hormone that also acts as a neurotransmitter in the brain. Among many other functions, it also facilitates birth and breastfeeding. Oxytocine is a small peptide made of nine amino acids (a nonapeptide) . The primary sequence is cysteine - tyrosine - isoleucine - glutamine - asparagine - cysteine - proline - leucine - glycine. In its active form oxytocine forms a cyclic structure. Which secondary bond is most suitable to form the cyclic structure?

Question

Quizplus · Accepted Answer

A disulfide bridge between the two cysteine residues is most suitable to form the cyclic structure of oxytocin. This is due to the ability of cysteine residues to form covalent disulfide bonds with each other, which can stabilize and rigidify the structure. Additionally, the formation of a disulfide bond between these two cysteine residues is critical for the biological activity of oxytocin.

Oxytocine Is a Mammalian Hormone That Also Acts as a Neurotransmitter