Amino Acids Can Join via Peptide Bonds Two amino acids The a-COOH and a-NH,+ groups of two amino acids Removal of a water molecule can react with the resulting loss of a water Peptide hond molecule to -formation of the CO-NH form a covalent amide bond Amino endAmino Acids Can Join via Peptide Bonds The a-COOH and a-NH3 + groups of two amino acids can react with the resulting loss of a water molecule to form a covalent amide bond