Lysozyme is an antibacterial enzyme found in animals. Residues Asp 101 and Arg 114 are required for efficient catalysis, although they are located at some distance from the active site Glu 35 and Asp 52. Substituting Ala for either Asp 101 or Arg 114 does not significantly alter the enzyme's tertiary structure, but significantly reduces its catalytic activity. Explain.

Lysozyme is an antibacterial enzyme found in animals. Residues Asp 101 and Arg 114 are required for efficient catalysis, although they are located at some distance from the active site Glu 35 and Asp 52. Substituting Ala for either Asp 101 or Arg 114 does not significantly alter the enzyme's tertiary structure, but significantly reduces its catalytic activity. Explain.

Biochemistry

6th Edition

ISBN:9781305577206

Author:Reginald H. Garrett, Charles M. Grisham

Publisher:Reginald H. Garrett, Charles M. Grisham

Chapter22: Gluconeogenesis, Glycogen Metabolism, And The Pentose Phosphate Pathway

Section: Chapter Questions

Problem 23P: Using the ActiveModel for aldose reductase, describe the structure of the TIM barrel motif and the...

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The active site of lysozyme contains two amino acid residues essential for catalysis: Glu35 and Asp52. The pKa values of the carboxyl side chains of these residues are 5.9 and 4.5, respectively. What is the ionization state(protonated or deprotonated) of each residue at pH 5.2, the pH optimum of lysozyme? How can the ionization states of these residues explain the pH-activity profile of lysozyme shown below?
Lysozyme residues Asp 101 and Arg 114 are required for effi cient catalysis, although they are located at some distance from the active site Glu 35 and Asp 52. Substituting Ala for either Asp 101 or Arg 114 does not signifi cantly alter the enzyme’s tertiary structure, but it signifi cantly reduces its catalytic activity. Explain.
The enzymatic activity of lysozyme is optimal at pH 5.2 and decreases above and below this pH value. Lysozyme contains two amino acid residues in the active site essential for catalysis: Glu35 and Asp52. The pK value for the carboxyl side chains of these two residues are 5.9 and 4.5 respectively. What is the ionization state of each residue at the pH optimum of lysozyme? How can the ionization states of these 2 amino acid residues explain the pH-activity profile of lysozyme?
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