Chapter Three
Amino Acids and Peptides
,Amino Acids
• Amino acid: a compound that contains
both an amino group and a carboxyl
group
• -Amino acid has an amino group
attached to the carbon adjacent to
the carboxyl group
• -carbon also bound to side chain
group, R
• R gives identity to amino acid
• Two steroisomers of amino acids
are designated L- or D-. Based on
similarity to glyceraldehdye
(Figure 3.2)
, Amino Acid Structure and Properties
• With the exception of glycine, all protein-derived
amino acids have at least one stereocenter (the -
carbon) and are chiral (stereoisomers)
• the vast majority of -amino acids have the L-
configuration at the -carbon (Proline is usually D)
• Side-chain carbons in other amino acids designated
with Greek symbols, starting at a carbon (…etc)
• Amino acids can be referred to by three-letter or one-
letter codes. Table 3.1 (KNOW THESE)
Amino Acids and Peptides
,Amino Acids
• Amino acid: a compound that contains
both an amino group and a carboxyl
group
• -Amino acid has an amino group
attached to the carbon adjacent to
the carboxyl group
• -carbon also bound to side chain
group, R
• R gives identity to amino acid
• Two steroisomers of amino acids
are designated L- or D-. Based on
similarity to glyceraldehdye
(Figure 3.2)
, Amino Acid Structure and Properties
• With the exception of glycine, all protein-derived
amino acids have at least one stereocenter (the -
carbon) and are chiral (stereoisomers)
• the vast majority of -amino acids have the L-
configuration at the -carbon (Proline is usually D)
• Side-chain carbons in other amino acids designated
with Greek symbols, starting at a carbon (…etc)
• Amino acids can be referred to by three-letter or one-
letter codes. Table 3.1 (KNOW THESE)
