When proteins undergo hydrolysis, water is added to the peptide bonds. Looking at the protein chain on the left we can predict the amino acids that will be formed from hydrolysis of the peptide link.

Step 1) Identify the peptide link.
(-CO-NH-)

Step 2) Split the bond through the -C-N- link.

Step 3) Add OH to the CO forming a COOH (carboxy) functional group and a H to the NH forming an NH₂(amino) functional group.

Look at the animation on the left.