Unformatted text preview: 3. This protein binds lysine-containing peptides. The pKa of Glu238 is decreased to 3.5 if the protein is saturated with substrate. a) Why does the pKa change in this way? b) What would happen to the T m of the enzyme in the presence of substrate? c) Why ? d) Compare ± H f of the free enzyme and enzyme-peptide complex? e) Why the difference? f) What is the electrostatic contribution to binding free energy of the substrate? (Hint, think LINKAGE!) g) If ALL of the binding energy was electrostatic, what would the stability difference be, quantitatively , between bound and free forms of the enzyme at pH 7.8? h) Where is Glu238 located and what does it do?...
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- Summer '09
- Enzyme, Enoch Baldwin, Protein Stability page