Textbook Question
Pepsin, a peptidase that hydrolyzes proteins, functions in the stomach at an optimum pH of 1.5 to 2.0. How is the rate of a pepsin-catalyzed reaction affected by each of the following conditions?
a. changing the pH to 5.0
Ch.16 Amino Acids, Proteins, and Enzymes
Timberlake14thChemistry: An Introduction to General, Organic, and Biological ChemistryISBN: 9781292472249
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Table of contents
- Ch.1 Chemistry in Our Lives19
- Ch.2 Chemistry and Measurements80
- Ch.3 Matter and Energy53
- Ch.4 Atoms and Elements58
- Ch.5 Nuclear Chemistry42
- Ch.6 Ionic and Molecular Compounds57
- Ch.7 Chemical Quantities and Reactions38
- Ch.8 Gases30
- Ch.9 Solutions50
- Ch.10 Acids and Bases and Equilibrium64
- Ch.11 Introduction to Organic Chemistry: Hydrocarbons77
- Ch.12 Alcohols, Thiols, Ethers, Aldehydes, and Ketones82
- Ch.13 Carbohydrates54
- Ch.14 Carboxylic Acids, Esters, Amines, and Amides91
- Ch.15 Lipids61
- Ch.16 Amino Acids, Proteins, and Enzymes84
- Ch.17 Nucleic Acids and Protein Synthesis86
- Ch.18 Metabolic Pathways and ATP Production73
Timberlake14thChemistry: An Introduction to General, Organic, and Biological ChemistryISBN: 9781292472249Not the one you use?Change textbook
Chapter 16, Problem 47b
Indicate whether each of the following describes a competitive or a noncompetitive enzyme inhibitor:
a. The inhibitor has a structure similar to the substrate.
Verified step by step guidance1
Understand the four levels of protein structure: Primary structure refers to the sequence of amino acids in a polypeptide chain. Secondary structure involves local folding patterns such as alpha helices and beta sheets. Tertiary structure describes the overall three-dimensional shape of a single polypeptide chain. Quaternary structure refers to the arrangement of multiple polypeptide chains or subunits in a protein.
Analyze the statement: 'Protein chains of collagen form a triple helix.' This describes the interaction and arrangement of multiple polypeptide chains.
Recognize that the triple helix is formed by three polypeptide chains interacting and stabilizing each other through hydrogen bonds and other forces.
Determine that this arrangement of multiple chains corresponds to quaternary protein structure, as it involves the organization of more than one polypeptide chain.
Conclude that the statement describes quaternary protein structure because it specifies the structural arrangement of multiple protein chains forming a triple helix.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Protein Structure Levels
Proteins have four levels of structure: primary, secondary, tertiary, and quaternary. Primary structure refers to the linear sequence of amino acids, secondary structure involves local folding patterns like alpha helices and beta sheets, tertiary structure is the overall 3D shape of a single polypeptide, and quaternary structure describes the assembly of multiple polypeptide chains into a functional protein.
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Summary of Protein Structure Concept 1
Collagen Structure
Collagen is a structural protein that primarily exhibits a unique triple helix formation in its secondary structure. This triple helix is composed of three polypeptide chains wound around each other, providing strength and support to various tissues, such as skin, bones, and cartilage.
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Helical Structures in Proteins
Helical structures, such as the triple helix found in collagen, are a common feature in protein secondary structures. These helices are stabilized by hydrogen bonds between the backbone of the polypeptide chains, contributing to the protein's stability and functionality in biological systems.
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Related Practice
Textbook Question
The following graph shows the activity versus pH curves for pepsin, sucrase, and trypsin. Estimate the optimum pH for each.
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Textbook Question
Refer to the graph in problem 16.45 to determine if the reaction rate in each condition will be at the optimum rate or not.
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a. trypsin, pH 5.0
Textbook Question
Indicate whether each of the following describes a competitive or a noncompetitive enzyme inhibitor:
d. The structure of the inhibitor is not similar to the substrate.
Textbook Question
Oxaloacetate is an inhibitor of succinate dehydrogenase.
a. Would you expect oxaloacetate to be a competitive or a noncompetitive inhibitor? Why?
Textbook Question
Methanol and ethanol are oxidized by alcohol dehydrogenase. In methanol poisoning, ethanol is given intravenously to prevent the formation of formaldehyde that has toxic effects.
b. Would ethanol compete for the active site or bind to a different site?