The following are practice questions designed to test your understanding of lecture and textbook material. Provide a written answer to the following questions. It may be necessary to use structures in order to answer the question.
Trypsin cleaves peptide bonds on the carboxyl side of lysine and arginine residues.
A cartoon representation of this aspartyl group in the active site is depicted below. The pKa of the side chain groups on lysine or arginine is approximately 10 and the pKa of the side chain of aspartic acid is approximately 4. The structure of N-benzoylglycyltyrosine is shown below. Each, however, recognizes different substrates. A biochemist isolates a new enzyme and suspects that a tyrosine residue donates a proton from its phenolic hydroxyl group as a critical step in the enzymatic mechanism.