The Biology Project: Biochemistry

Large Molecules Problem Set

Problem 9: Identification of a hydrophobic amino acid

Tutorial to help answer the question

Which amino acid has a hydrophobic side chain?

Chemical Structures of Isoleucine (C6H13NO2), asparagine (C4H8N2O3 ), threonine (C4H9NO3), glycine (C2H5NO2 ), glutamic acid (C5H9NO4 )


The hydrophobic amino acids
There are 20 different amino acids found in proteins. The side chains (R-groups) differ in chemical properties. Some are polar, but uncharged. Some are polar and normally have a positive or negative charge in solution.

The eight amino acids shown below have distinctly hydrophobic side chains. Note that the side chains are composed almost entirely of C-C and C-H chemical bonds, being either entirely hydrocarbons, or mostly hydrocarbons with a single polar atom.

chemical structure of alanine (C3H7NO2 ) Chemical structure of valine C5H11NO2 Chemical structure of leucine C6H13NO2 Chemical structure isoleucine C6H13NO2 Chemical structure of methionine C5H11NO2S
Molecular structure of alanine C3H7NO2 Molecular structure for valine C5H11NO2 Molecular structure of leucine C6H13NO2 Molecular structure of isoleucine C6H13NO2 Molecular structure of methionine C5H11NO2S

Chemical structure of tyrosine C9H11NO3 Chemical structure for phenylalanine C9H11NO2 Chemical structure of tryptophan C9H11NO2
Molecular structure for tyrosine C9H11NO3 Molecular structure for phenylalanine C9H11NO2 Molecular structure for tryptophan C9H11NO2

problem 9 answer problem 10

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