An eager young biochemist was digesting the same protein in three different tubes. Each tube had a separate protease:

• trypsin
• chymotrypsin, which cleaves at the carboxyl side of the three large and bulky aromatic amino acids
• Glu-C, which cleaves C-terminally to Glu or Asp

After digestion, the samples were analysed by mass spectrometry but -- oh no! -- the biochemist forgot to label their tubes.

Luckily, they have you to help them.

Look at the sequences from each sample below to deduce (if possible) which enzyme had been used in which tube.