Chapter 3: Amino Acids and Peptides
Linear polymers of amino acids
For all amino acids the alpha carbon is bonded to 4 different groups, creating a
chiral center
Grouping Amino Acids
o Non-polar aliphatic
o Aromatic
o Polar, Uncharged
o Polar, +ve charged
o Polar, -ve charged
Nonpolar, Aliphatic Amino Acids (Non-Polar)
Glycine, Alanine, Valine,
Leucine, Isoleucine, Proline,
Methionine
Buried within the core of the
protein (since side chains
don’t want to interact with
Water)
All are non-polar
Determine whether
something is polar/non-polar
you look for
o Charge
For these amino acids, there is no charge for the side chains
o Hydrogen Bonding Capability
For these amino acids, there is no Hydrogen bonding capability for
the side chains
Glycine is the smallest (non chiral): Hydrogen side chain
Methionine: sulfur group in the side chains (and also cystine carries one)
Proline: its side chains has a ringed structure (found at polypeptide turns usually in
combination with glycine)
Aromatics
Ring groups as side chains
Linear polymers of amino acids
For all amino acids the alpha carbon is bonded to 4 different groups, creating a
chiral center
Grouping Amino Acids
o Non-polar aliphatic
o Aromatic
o Polar, Uncharged
o Polar, +ve charged
o Polar, -ve charged
Nonpolar, Aliphatic Amino Acids (Non-Polar)
Glycine, Alanine, Valine,
Leucine, Isoleucine, Proline,
Methionine
Buried within the core of the
protein (since side chains
don’t want to interact with
Water)
All are non-polar
Determine whether
something is polar/non-polar
you look for
o Charge
For these amino acids, there is no charge for the side chains
o Hydrogen Bonding Capability
For these amino acids, there is no Hydrogen bonding capability for
the side chains
Glycine is the smallest (non chiral): Hydrogen side chain
Methionine: sulfur group in the side chains (and also cystine carries one)
Proline: its side chains has a ringed structure (found at polypeptide turns usually in
combination with glycine)
Aromatics
Ring groups as side chains
