Classification of Amino Acids Flashcards
Structure of Amino Acids
Acidic AAs
- Aspartic Acid
- Glutamic Acid
Aspartic Acid
Asp, D
aspartate - the anionic/deprotonated form
(how this amino acid is observed at physiological pH)
Glutamic Acid
Glu, E
glutamate - the anionic/deprotonated form
(how this AA is observed at physiological pH)
Basic AAs
- Lysine
- Arginine
- Histidine
Lysine
Lys, K
pKa = 10
cationic/protonated at physiological pH
Arginine
Arg, R
pKa = 12 at physiological pH
cationic/protonated at physiological pH
Histidine
His, H
pKa = 6.5 at physiological pH
can either be protonated (acidic) or deprotonated (basic)
Hydrophobic (Nonpolar) AAs
- Glycine
- Alanine
- Valine
- Leucine
- Isoleucine
- Phenylalanine
- Tryptophan
Characteristics of Hydrophobic/Nonpolar AAs
- either have aliphatic or aromatic side chains
- hydrophobic residues tend to associate with each other rather than with water
- therefore are found on the interior of folded globular proteins, away from water
- the larger the hydrophobic group, the greater the hydrophobic force repelling it from water
Glycine
Gly, G
aliphatic side chain
Alanine
Ala, A
aliphatic side chain
Valine
Val, V
aliphatic side chain
Leucine
Leu, L
aliphatic side chain
Isoleucine
Ile, I
aliphatic side chain