15 - What would be the lowest possible ionization state for this amino acid? OH

Question

15 - What would be the lowest possible ionization state for this amino acid? OH NH A) 2 B)+1 C)0 D)-1 E) -2 16- Amino acids with acidic variable side chains, at any pH below the pl of the amino acid, the population of amino acids in solution will have: A) a net negative charge. B) a net positive charge C) no charged groups. D) no net charge. E) positive and negative charges in equal concentration 17- To determine the isoelectric point of a basic amino acid the pk, values of which equilibrium reactions of ionization should be used? A) +2 to +1 and +1 to 0 B) +1 to 0 and 0 to -1 C) 0 to -1 and -1 to-2 D) +2 to +1 and 0 to -1 E) +2 to +1 and-1 to -2 18 - Which of the following amino acids has the highest isoelectric point? OH O CHa OH

Explanation / Answer

This is aspartic acid and lowest possible ionization state for this amino acid is -2. When pH above 9.67 both the COOH groups will have negative charge while this NH2 will have 2. While pH below 2.19 both COOH have zero charge while NH3 will have +1.

The population will have a net positive charge (option B). This is because t Ph below the PI the acidic amino acids will be deprotonated COOH groups while protonated NH2 groups having charge 0 and +1 respectively hence having a net positive charge.

The determination the isoelectric point of a basic amino acid the pka should be chosen by

D) +2 to +1 and 0 to -1

Related Questions

Navigate

• Browse (All)
• Browse 1
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.