A Common Reaction of Two Cysteine Residues in Proteins Results

Question

A common reaction of two cysteine residues in proteins results in the formation of ____.
A) thioester bonds
B) disulfide bonds
C) dithiol bonds
D) thioether bonds
E) none of the above

Accepted Answer

Two cysteine residues can react through the oxidation of their sulfhydryl groups to form a covalent bond called a disulfide bond or disulfide bridge. This bond is important for the stability and function of many proteins, especially those that are secreted or located on cell membranes. Thioester bonds (A), dithiol bonds (C), and thioether bonds (D) can also be formed with cysteine residues but they require different chemical reactions.