Amino acid side chain pKas and extended lore

Question 1

Lysine-
(draw and label R pKa)

Answer 1

pKa ~10.5

Question 2

Arginine-
(draw and label R pKa)

Answer 2

pKa ~12.5

Question 3

Aspartic acid (aspartate)-
(draw and label R pKa)

Answer 3

pKa ~3.9

Question 4

Glutamic acid-
(draw and label R pKa)

Answer 4

pKa ~4.1

Question 5

Histidine-
(draw and label R pKa)

Answer 5

pKa ~6.0

Question 6

Tyrosine-
(draw and label R pKa)

Answer 6

pKa ~10.5

Question 7

Cysteine-
(draw and label R pKa)

Answer 7

pKa ~8.4

Question 8

pH > pKa

Answer 8

Proton off

Question 9

pH=pKa

Answer 9

50% on, 50% off

Question 10

pH < pKa

Answer 10

Proton on

Question 11

Amine pKa

Answer 11

~9-11

Question 12

Alcohol pKa

Answer 12

~15

Question 13

Thiol pKa

Answer 13

9-11

Question 14

Aldehyde pKa

Answer 14

17-20

Question 15

Carboxy acid pKa

Answer 15

3-5

Question 16

Phosphoryl group pKa
(secretly 3 :0 )

Answer 16

~2, ~7, ~12

Question 17

List the 7 amino acids with important pKas (charged side chains)

((bonus if you can name the values!))

Answer 17

K, R, D, E, H, Y, C

Lysine, Arginine, Aspartic acid, Glutamic acid, Histidine, Tyrosine, Cysteine

Lys, Arg, Asp, Glu, His, Tyr, Cys

Question 18

DRAW the 7 amino acids with important pKas (charged side chains)

Answer 18

K, R, D, E, H, Y, C

Lysine, Arginine, Aspartic acid, Glutamic acid, Histidine, Tyrosine, Cysteine

Lys, Arg, Asp, Glu, His, Tyr, Cys

Question 19

Main chiral configuration of 18 amino acids (bonus for outliers)

Answer 19

S, Cysteine is R

Question 20

How many amino acids are chiral?

Answer 20

19

Question 21

Which amino acid isn’t chiral?

Answer 21

Glycine, just got that H