Trypsin and chymotrypsin are members of the family of serineproteases. They cleave peptide bonds at the C-terminal end ofspecific residues. Chymotrypsin recognizes aromatic residues, whiletrypsin recognizes lysine and arginine. The recognition of aparticular side chain (side chain specificity) is fully determinedby the structure and properties of the binding pocket. In the caseof chymotyipsin the binding pocket is hydrophobic and is wideenough to accommodate an aromatic ring. Given what you know aboutthe properties of Lys/Arg side chains, what can you say about thesize/shape and possible interactions that would provide thesubstrate specificity in the case of trypsin? What amino acidresidues from the trypsin molecule would you expect to find in thebinding site?
