Biochemistry: Concepts and Connections (2nd Edition)
2nd Edition
ISBN: 9780134641621
Author: Dean R. Appling, Spencer J. Anthony-Cahill, Christopher K. Mathews
Publisher: PEARSON
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Textbook Question
Chapter 6, Problem 22P
A Leu → Ala mutation at a site buried the core of the enzyme lysozyme is found to be destabilizing. Explain observed effect of this mutation on lsozyme stability by predicting how enthalpy (ΔH''), conformational entropy (ΔS0peptide), and the hydrophobic effect (ΔS0solvent) are expected to change for the mutant compared to wild-type lysozyme. Explain how for unfolding affected by your predicted changes enthalpy or entropy.
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Lysozyme is an enzyme that hydrolyzes bacterial cell wall polysaccharides. When this reaction is carried out in the presence of H218O, it is observed that there is retention of configuration at the C1 carbon of the D site sugar as shown below:
Would this result suggest that the enzyme mechanism involves the direct nucleophilic attack of water at C1 or that the enzyme mechanism involves attack by a nucleophilic amino acid side chain of the enzyme that generates a transient covalent intermediate?
Lysozyme is an enzyme that hydrolyzes bacterial cell wall polysaccharides. When this reaction is carried out in the presence of H218O, it is observed that there is retention of configuration at the C1 carbon of the D site sugar as shown below
Two key amino acid side chains (an Asp and a Glu) essential for lysozyme’s catalytic activity are positioned above and below the C1-O bond that is cleaved as shown below. Suggest a plausible mechanism for the reaction that starts with a nucleophilic attack at C1.
The enzyme lysozyme kills certain bacteria by attacking a
sugar called N-acetylglucosamine (NAG) in their cell walls.
At an enzyme concentration of 2 × 10-6 M, the maximum
rate for substrate (NAG) reaction, found at high substrate
concentration, is 1 × 10-6 mol L¯'s1. The rate is reduced
by a factor of 2 when the substrate concentration is
reduced to 6 x 10-6 M. Determine the Michaelis-Menten
constants Km and k, for lysozyme.
Chapter 6 Solutions
Biochemistry: Concepts and Connections (2nd Edition)
Ch. 6 - Prob. 1PCh. 6 - Bovine pancreatic trypsin inhibitor (BPTI; Figure...Ch. 6 - A schematic structure of the subunit of...Ch. 6 - In the protein adenylate kinase, the C-terminal...Ch. 6 - Give two reasons to explain why a proline residue...Ch. 6 - Consider a small protein containing 101 amino acid...Ch. 6 - a. Based on a more conservative answer to Problem...Ch. 6 - The following sequence is part of a globular...Ch. 6 - a. A protein is found to be a tetramer of...Ch. 6 - Under physiological conditions, the protein...
Ch. 6 - Theoretical and experimental measurements show...Ch. 6 - The peptide hormone vasopressin is used in the...Ch. 6 - A protein gives under conditions of buffer...Ch. 6 - A protein gives a single band on SDS get...Ch. 6 - It has been postulated that the normal...Ch. 6 - Below are shown two views of the backbone...Ch. 6 - Do you expect a Pro Gly mutation in a...Ch. 6 - Rank the following in terms of predicted rates...Ch. 6 - Shown below are two cartoon views of the small...Ch. 6 - Prob. 20PCh. 6 - In most cases, mutations in the core of protein...Ch. 6 - A Leu Ala mutation at a site buried the core of...Ch. 6 - Disulfide bonds have been shown to stabilize...Ch. 6 - Cartoon renderings of the proteins Top 7 and adaH2...
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