Book cover for Organic chemistry with biological applications

Organic chemistry with biological applications

John E. McMurry

ISBN #9781285842912

3rd Edition

1,528 Questions

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13,325 Students Helped

Homework Questions

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Summary
Learning Objectives
Key Concepts
Example Problems
Explanations
Common Mistakes

Summary

This section covers the fundamental chemistry of amino acids, peptides, and proteins. It explains how the unique structural features of amino acids, including their zwitterionic nature and chirality, contribute to the formation of peptide bonds during protein biosynthesis. Detailed methods for peptide sequencing (such as Edman degradation) and synthesis (both solution-phase and solid-phase) are described, along with the principles behind enzyme catalysis, including substrate binding and transition state stabilization. These concepts are essential for understanding both natural biological processes and the development of biomolecular tools in research and industry.

Learning Objectives

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Key Concepts

CONCEPT

DEFINITION

Definition: The study of molecular reactivity via polar covalent bonds where differences in electronegativity create dipole moments, guiding acid–base behavior.

The study of molecular reactivity via polar covalent bonds where differences in electronegativity create dipole moments, guiding acid–base behavior. •

Example Problems

Example 1

How many of the $\alpha$ -amino acids shown in Table 19.1 contain aromatic rings? How many contain sulfur? How many contain alcohols? How many contain hydrocarbon side chains?

Example 2

Of the 19 L amino acids, 18 have the $S$ configuration at the $\alpha$ carbon. Cysteine is the only $\mathrm{L}$ amino acid that has an $R$ configuration. Explain.

Example 3

The amino acid threonine, $(2 S, 3 R)-2$ -amino-3-hydroxybutanoic acid, has two chirality centers. (a) Draw threonine, using normal, wedged, and dashed lines to show dimensionality. (b) Draw a diastereomer of threonine, and label its chirality centers as $R$ or $S$.

Example 4

Hemoglobin has $\mathrm{p} I=6.8$. Does hemoglobin have a net negative charge or net positive charge at $\mathrm{pH}=5.3 ?$ At $\mathrm{pH}=7.3 ?$

Example 5

What alkyl halides would you use to prepare the following $\alpha$ -amino acids by the amidomalonate method? (a) Leucine (b) Histidine (c) Tryptophan (d) Methionine
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Step-by-Step Explanations

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Common Mistakes

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