When a molecule of formaldehyde reacts by cross-linking peptide bonds, which molecule is produced?

When a molecule of formaldehyde reacts by cross-linking peptide bonds, which molecule is produced?

• A. Hydrogen gas
• B. Oxygen
• C. Water
• D. Methane

Answer: (C)

Formaldehyde cross-linking between peptide chains occurs through a condensation reaction that forms a methylene bridge (-CH2-) linking two amino groups. Formaldehyde first reacts with a primary amine to form a hydroxymethyl adduct, and when two such adducts come together, they release a molecule of water to form the methylene crosslink. So water is produced in this process. Hydrogen, oxygen, or methane aren’t the byproducts of this specific condensation reaction that creates the crosslink.

Formaldehyde cross-linking between peptide chains occurs through a condensation reaction that forms a methylene bridge (-CH2-) linking two amino groups. Formaldehyde first reacts with a primary amine to form a hydroxymethyl adduct, and when two such adducts come together, they release a molecule of water to form the methylene crosslink. So water is produced in this process. Hydrogen, oxygen, or methane aren’t the byproducts of this specific condensation reaction that creates the crosslink.