Methods of controlled cleavage

A method comprising:

• (a) contacting a polypeptide with an acetylation agent under conditions sufficient to produce an acetylated amino acid at a terminus of the polypeptide;
• and
• (b) contacting the polypeptide with an enzyme that catalyzes the removal of the acetylated amino acid from the terminus of the polypeptide.

A method comprising:

• (a) contacting a polypeptide with a handle peptide under ligation conditions sufficient to ligate the handle peptide to an amino acid at a terminus of the polypeptide;
• and
• (b) contacting the polypeptide with an enzyme that catalyzes the removal of the handle peptide-ligated amino acid from the terminus of the polypeptide.

An acylpeptide hydrolase comprising an amino acid sequence that is at least 85% identical to SEQ ID NO:

• 1, wherein the amino acid sequence has one or more substitutions, insertions, and/or deletions relative to SEQ ID NO:
• 1.