Textbook Question
Both α-keratin and tropocollagen have helical secondary structure. How do these molecules differ in (a) amino acid composition and (b) three-dimensional structure?
Ch.18 Amino Acids and Proteins
McMurry8th EditionFundamentals of General, Organic, and Biological ChemistryISBN: 9780134015187
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Table of contents
- Ch.1 Matter and Measurements27
- Ch.2 Atoms and the Periodic Table20
- Ch.3 Ionic Compounds8
- Ch.4 Molecular Compounds23
- Ch.5 Classification & Balancing of Chemical Reactions12
- Ch.6 Chemical Reactions: Mole and Mass Relationships28
- Ch.7 Chemical Reactions: Energy, Rate and Equilibrium64
- Ch.8 Gases, Liquids and Solids24
- Ch.9 Solutions52
- Ch.10 Acids and Bases25
- Ch.11 Nuclear Chemistry22
- Ch.12 Introduction to Organic Chemistry: Alkanes57
- Ch.13 Alkenes, Alkynes, and Aromatic Compounds47
- Ch.14 Some Compounds with Oxygen, Sulfur, or a Halogen50
- Ch.15 Aldehydes and Ketones45
- Ch.16 Amines42
- Ch.17 Carboxylic Acids and Their Derivatives57
- Ch.18 Amino Acids and Proteins82
- Ch.19 Enzymes and Vitamins63
- Ch.20 Carbohydrates44
- Ch.21 The Generation of Biochemical Energy65
- Ch.22 Carbohydrate Metabolism45
- Ch.23 Lipids42
- Ch.24 Lipid Metabolism33
- Ch.25 Protein and Amino Acid Metabolism24
- Ch.26 Nucleic Acids and Protein Synthesis45
McMurry8th EditionFundamentals of General, Organic, and Biological ChemistryISBN: 9780134015187Not the one you use?Change textbook
Chapter 18, Problem 33
If the same peptide found in Problem 18.32 is subjected to acid hydrolysis, how many fragments will result? Why?
Ala-Phe-Lys-Cys-Gly-Asp-Arg-Leu-Leu-Phe-Gly-Ala
Verified step by step guidance1
Identify the peptide sequence from Problem 18.32 (not provided here, but you would need to refer to it to proceed). A peptide is a chain of amino acids linked by peptide bonds.
Understand that acid hydrolysis breaks peptide bonds, which are the covalent bonds between the carboxyl group of one amino acid and the amino group of the next amino acid.
Count the number of peptide bonds in the peptide sequence. The number of peptide bonds is equal to the number of amino acids in the peptide minus one.
Realize that during acid hydrolysis, each peptide bond is cleaved, resulting in individual amino acids as fragments. Therefore, the number of fragments will equal the number of amino acids in the peptide.
Conclude that the number of fragments corresponds to the total number of amino acids in the peptide, and this happens because acid hydrolysis completely breaks all peptide bonds.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Acid Hydrolysis
Acid hydrolysis is a chemical reaction where water and an acid are used to break down compounds. In the context of peptides, this process cleaves the peptide bonds between amino acids, resulting in the release of individual amino acids or smaller peptide fragments. Understanding this reaction is crucial for predicting the outcome of peptide fragmentation.
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1:12
Acidic Hydrolysis Concept 1
Peptide Structure
Peptides are short chains of amino acids linked by peptide bonds. The sequence and number of amino acids determine the peptide's properties and behavior during hydrolysis. Knowing the specific structure of the peptide in question is essential to accurately predict how many fragments will be produced after acid hydrolysis.
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3:07Peptides Concept 1
Fragmentation Analysis
Fragmentation analysis involves examining the products formed after a chemical reaction, such as hydrolysis. By analyzing the resulting fragments, one can determine the number of distinct pieces generated from the original peptide. This concept is vital for understanding the implications of the hydrolysis process on the peptide's composition.
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06:11Dimensional Analysis
Related Practice
Textbook Question
Draw the structure of the following amino acids, dipeptides, and tripeptides at low pH (pH 1) and high pH (pH 14). At each pH, assume that all functional groups that might do so are ionized.
a. Val
Textbook Question
Another endoprotease is trypsin. Trypsin hydrolyzes peptide bonds on the carboxyl side of lysine and arginine. If the following peptide sequence is hydrolyzed by trypsin, how many fragments will there be? Use the three-letter amino acid abbreviations to write the fragments out.
Ala-Phe-Lys-Cys-Gly-Asp-Arg-Leu-Leu-Phe-Gly-Ala
Textbook Question
Draw the structure of the following amino acids, dipeptides, and tripeptides at low pH (pH 1) and high pH (pH 14). At each pH, assume that all functional groups that might do so are ionized.
e. Gln-Ala-Asn
Textbook Question
For each of the conjugated proteins described, identify to which class of conjugated protein it belongs.
c. Phosphate groups are attached to this protein.
Textbook Question
Draw the structure of the following amino acids, dipeptides, and tripeptides at low pH (pH 1) and high pH (pH 14). At each pH, assume that all functional groups that might do so are ionized.
d. Glu-Asp