a. Identify the differences between D and L amino acids b. Define the isoelectri

Question

a. Identify the differences between D and L amino acids b. Define the isoelectric point (pl) pH at wwich We amino ais neutral auino acl neutra c. Calculate the approximate pl of an amino acid given the pKa values for all ionizable groups. d. Identify the structures of the 20 common amino acids and how they can be categorized into charged, hydrophilic, hydrophobic, and aromatic subfamilies. State the 3-letter and 1-letter abbreviations for the 20 common amino acids e. f. Describe the protonation states of all amino acids with ionizable groups.

Explanation / Answer

a, D and L are enantiomers. L amino acid is an enantiomer that rotates the plane polarized light in the anticlockwise direction, while D enantiomer rotates the light in the clockwise direction.

c. Calculation of pI for simple amino acids is calculated as,

pI = (pKa + pKb)/2 , where pKa is for the carboxylic acid and pKb is for the amine.

f. At pH >> pKa, the ionizable group will be deprotonated. For carboxylic acids, this means that the group will be negatively charged; amines will be neutral.

At pH << pKa, the ionizable group will be protonated. For carboxylic acids, this means that the group will be neutral; amines will be positively charged i.e protonated.

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

---

---

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