Amino Acid Ionisation

Question 1

What is the predominant form of a carboxyl group (Asp/Glu) below its pKa?

Answer 1

-COOH

Question 2

What is the predominant form of a carboxyl group (Asp/Glu) above its pKa?

Answer 2

-COO-

Question 3

What is the predominant form of an amino group (Lys) below its pKa?

Answer 3

-NH3+

Question 4

What is the predominant form of an amino group (Lys) above its pKa?

Answer 4

-NH2

Question 5

What is the predominant form of a thiol group (Cys) below its pKa?

Answer 5

-SH

Question 6

What is the predominant form of a thiol group (Cys) above its pKa?

Answer 6

-S-

Question 7

What is the predominant form of a imidazole group (His) below its pKa?

Answer 7

-NH+

Question 8

What is the predominant form of a imidazole group (His) above its pKa?

Answer 8

-NH

Question 9

What is the predominant form of a phenolic OH group (Tyr) below its pKa?

Answer 9

-OH

Question 10

What is the predominant form of a phenolic OH group (Tyr) above its pKa?

Answer 10

-O-

Question 11

What is the predominant form of a guanidinium group (Arg) below its pKa?

Answer 11

+ charge

Question 12

What is the predominant form of a guanidinium group (Arg) above its pKa?

Answer 12

no charge