Question

24. Explain the energetic benefits of making the enzyme active state rather than to the substrate conformation. Also explain how contribute to enzyme action. In other words, how do these weak intera enzyme and the transition state lower the activation energy?) of making the enzyme active site complementary to the transition nation. Also explain how multiple weak interactions words, how do these weak interactions between the 25. 1/F. The pk's of titratable groups of amino acids remain constant irrespective of chemical sequence environment. 26. Look for the slide in Lecture 6 titled "Binding/Entropy Reduction". Using the images in this screen, explain how an enzyme further lowers the activation energy by reducing entropy. 25 p-Nitrophenol (mol/mol of enzyme) 27. In the progress curve to the right, one observes the so- called "burst phase kinetics" that illustrate the action of proteases and other enzymes. Explain the shape of the curve. In other words, why would there appear to be an initial burst at the onset of the enzymatic reaction? Time (min) 28. How do serine proteases interact with their peptide/protein ligands in a sequence-specific way? In the peptide below, identify the peptide bonds that will be cut by the three different kinds of serine proteases. (EXTRA CREDIT: identify the sequence of the peptide and give an approximate pH of the solution.) 29. Hypothesize what would happen if there's a mutation in the oxyanion hole of serine proteases- for instance, if the Gly193 is mutated into a Pro, a Glu, or a Trp. Asp 30. Describe the roles of each residue in the so-called "catalytic triad" of serine proteases. 102 31. The so-called "tetrahedral intermediate" (pictured on the right) occurs during the transition state of serine protease action. Is this a stable or an unstable structure? Explain. Tetrahedral intermediate

Answer 1

only first question will be answered as per multiple question guideline:

24.

Multiple weak interaction which play role in enzymatic actions :

• Electrostatic interactions
• Hydrogen bonds
• Van der Waals
• Hydrophobic.

Non-covalent interaction between the active site and the substrate is one of ways through which enzyme bound states are stabilized. These interaction hold the substrate in a particular orientation and ES complex.

Activation energy energy of reaction and $\Delta$G (free energy) are related :

Free energy have two components: enthalpy change ($\Delta$H), and entropy change ($\Delta$S).

Enzymes help a reaction by stabilizing the transition state intermediate.It lowers the energy barrier or activation energy (energy required to promote the formation of transition state intermediate).Enzyme binds the transition state intermediate tightly, and the binding energy of this interaction effectively reduces the activation energy.

$\Delta$G = -RT lnK

.The binding of enzyme to the transition state is exergonic, and the energy released by this binding reduces the activation energy for the reaction and greatly increases the reaction rate.

From above discussion energetic benefits of making active site of enzyme complementary to transition state than substrate , as it the barrier of activation energy which is required to cross for cross-over from transition state to products, being complementary to substrate may not affect this energy requirements.