Amino Acids

Question 1

Amino acids with Aliphatic side chains

Answer 1

Glycine - Gly,G

Alanine - Ala, A

Valine - Val, V

Leucine - Leu - L

Isoleucine - ILe, I

Question 2

Amino acid with no chiral centre

Answer 2

Glycine

Question 3

Amino acid with two chiral centres

Answer 3

Isoleucine

Question 4

Amino acids with non polar aliphatic side chains

Answer 4

Methionine - Met, M

Proline - Pro, P

Question 5

Amino acids with basic/hydrophilic side chains

Answer 5

Lysine - Lys, K
Lysines side chains have a pKa of 10 so is fully protonated at pH 7

Arginine - Arg, R
Has highest pKa of 13 so is always protonated

Histidine - His, H
Has pKa of 7 so is 50% ionised/protonated at physiological pH - useful for enzyme transporters

Question 6

Amino acids with acidic/hydrophilic side chains

Answer 6

Aspartate - Asp, D

Glutamate - Glu, E