CHEM 3500 - Amino Acid Alphabet

A

Alanine (Ala), hydrophobic

C

Cysteine (Cys), hydrophilic and polar

D

Aspartate/Aspartic Acid (Asp), hydrophilic and acidic

E

Glutamate/Glutamic Acid (Glu), hydrophilic and acidic

F

Phenylalanine (Phe) aromatic and in the para position, hydrophobic

G

Glycine (Gly). Non-chiral aka not optically active. Hydrophobic

H

Histidine (His), Basic, Hydrophilic and basic

I

Isoleucine (Ile), sec-butyl. Hydrophobic

K

Lysine (Lys) basic and hydrophilic.

L

Leucine (Leu), hydrophobic

M

Methionine (Met), hydrophobic

N

Asparagine (Asn), Polar and hydrophilic

P

Proline (Pro), hydrophobic

Q

Glutamine (Gln). polar and hydrophilic.

R

Arginine (Arg) positively charged. Basic and hydrophilic.

S

Serine (Ser). Polar and hydrophilic

T

Threonine (Thr). Polar and hydrophilic

V

Valine (Val) and hydrophobic.

W

Tryptophan (Trp) aromatic. Mainly hydrophobic, can be hydrophilic bc of indole group.

Y

Tyrosine (Tyr) aromatic. Polar and hydrophilic

Negatively Charged (Acidic) Amino Acids, Hydrophilic

1. Aspartate (Asp, D)

2. Glutamate (Glu, E)

Hydrophobic Amino Acids

1. Glycine (Gly, G)

2. Alanine (Ala, A)

3. Valine (Val, V)

4. Leucine (Leu, L)

5. Isoleucine (Ile, I)

6. Methionine (Met, M)

7. Proline (Pro, P)

8. Phenylalanine (Phe, F)

9. Tryptophan (Trp, W) - CAN BE HYDROPHILIC BC OF INDOLE GROUP

Polar Amino Acids, Hydrophilic

1. Serine (Ser, S)

2. Threonine (Thr, T)

3. Tyrosine (Tyr, Y) - CAN BE HYDROPHILIC BC OF -OH ON AROMATIC RING

4. Cysteine (Cys, C)

5. Asparagine (Asn, N)

6. Glutamine (Gln, Q)

Positively (Basic) Charged Amino Acids, Hydrophilic

1. Lysine (Lys, K)

2. Arginine (Arg, R)

3. Histidine (His, H)

Nonessential vs essential amino acids

Table of Typical pKa Values of Ionizable Groups in Proteins