Properties of Amino Acids Flashcards
1
Q
Glycine (Gly, G)
A
- hydrophobic, aliphatic
- nonpolar but can be on surface proteins, due to ability to make tight turns
- smallest amino acid
2
Q
Alanine (Ala, A)
A
- hydrophobic, aliphatic
- nonpolar
3
Q
Valine (Val, V)
A
- hydrophobic, aliphatic
- nonpolar
4
Q
Leucine (Leu, L)
A
- hydrophobic, aliphatic
- nonpolar
5
Q
Isoleucine (Ile, I)
A
- hydrophobic, aliphatic
- nonpolar
6
Q
Methionine (Met, M)
A
- hydrophobic, technically not aliphatic
- nonpolar
- has a sulfur group that displays the same properties as aliphatic
7
Q
Proline (Pro, P)
A
- hydrophobic, aliphatic
- ring
- side chain is bonded to both nitrogen and alpha carbon, so no rotation and kinks
- can be on surface of proteins, like glycine
- NH2+ instead of NH3+
8
Q
Phenylalanine (Phe, F)
A
- hydrophobic
- nonpolar
- aromatic ring
- phenyl ring
9
Q
Tyrosine (Tyr, Y)
A
- hydrophobic
- nonpolar
- aromatic ring
- has -OH group
- weakly acidic at high pH
- can absorb 280 nm
10
Q
Tryptophan (Trp, W)
A
- hydrophobic
- non polar
- aromatic ring
- indole group joined to a methylene group
- can form a weak H-bond
- can absorb 280 nm
11
Q
Asparagine (Asn, N)
A
- polar, uncharged (neutral)
- contains a terminal carboxamide
- can form interactions with water and H-bonds
12
Q
Glutamine (Gln, Q)
A
- polar, uncharged (neutral)
- contains terminal carboxamide
- can form interactions with water and H-bonds
13
Q
Serine (Ser, S)
A
- polar, uncharged (neuteral)
- hydrophilic and reactive
- can form weak H-bonds
- can be post-modified
- involved in acid-base reactions
14
Q
Cysteine (Cys, C)
A
- polar
- weakly acidic
- sulfhydryl group
- active site of enzymes
- can form disulfide bonds
- can ionize at 8.3 pH
15
Q
Threnoine (Thr, T)
A
- polar, uncharged (neutral)
- hydropholic and reactive
- can form weak H-bonds
- can be post-modified
16
Q
Lysine (Lys, K)
A
- polar
- basic
- hydrophilic
- an amino group
- can form ionic bonds (proton acceptor)
17
Q
Arginine (Arg, R)
A
- polar
- basic
- hydrophilic
- guanidinium group
- can form ionic bonds (proton acceptor)
18
Q
Histidine (His, H)
A
- polar
- basic
- hydrophilic
- imidazole group
- can form ionic bonds (proton acceptor)
19
Q
Glutamate (Glu, E)
A
- polar
- acidic
- hydrophilic
- carboxylic acid
- at phys. pH lacks proton (proton donor)
- can form ionic bonds
20
Q
Aspartate (Asp, D)
A
- polar
- acidic
- hydrophilic
- carboxylic acid
- at phys. pH lacks proton (proton donor)
- can form ionic bonds
21
Q
Determine the pKa of the ionizing side chain:
Arginine (Arg, R)
A
12.5
22
Q
Determine the pKa of the ionizing side chain:
Aspartic acid (Asp, D)
A
3.9
23
Q
Determine the pKa of the ionizing side chain:
Cysteine (Cys, C)
A
8.3
24
Q
Determine the pKa of the ionizing side chain:
Glutamic acid (Glu, E)
A
4.2
25
# Determine the pKa of the ionizing side chain:
Lysine (Lys, K)
10.0
26
# Determine the pKa of the ionizing side chain:
Tyrosine (Tyr, Y)
10.1
27
# Determine the pKa of the ionizing side chain:
Histidine (His, H)
6.0
