Introduction to Enzyme Structure - Trypsin

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  Distances (Å):   Width   Height
  Active Site Residues    Zoom in
  Inhibitor   Specificity
  Binding Pocket (Wire)   (CPK)
  Reset   MMClrs

1. Trypsin is about 250 amino acids. Hit the Rotate buttons to get an idea of the shape of this enzyme. Most enzymes are globular (or ball like). Hit the Distances button to get an idea of the size of this enzyme. Hit the button again to remove the distances.

  2. All enzymes have chemical groups which perform the catalysis. In the case of trypin these are amino acid side chains. Note that some proteins utilize non-amino acid cofactors to help with the catalysis. Hit the Active Site Residues button to highlight the active site residues in Trypsin. These three residues (Asp102, His57, and Ser195) form the 'catalytic triad' and all three are important for catalysis. Note that these same residues perform similar functions in other serine proteases.
3. Substrate binding. All enzymes have a site on their surface which binds substrate. Hit the Inhibitor button to display the bound inhibitor (an inhibitor was used in these case to prevent hydroylsis). The inhibitor is colored yellow.
4. Substrate specificity. Enzymes form specific interactions with their substrates. Hit the Specificity button to illustate the electrostatic interaction between the Arg residue of the inhibitor (colored blue) and Asp189 in the enzyme.
5. Dipole-Dipole Interactions. The contacts between substrate and enzyme can be as numerous as those found between the amino acids in the folded protein. Hit the Binding Pocket (wire) to display the enzyme as CPK and the inhibitor as black wires. Hit the (CPK) button to show both the inhibitor and the enzyme in CPK mode.