Glutamic acid pKas are 22 43 and 97 The isoelectric point fo

Glutamic acid pKa\'s are 2.2, 4.3, and 9.7. The isoelectric point for the acid is a. 3.25 b. 4.3 c. 5.4 d. 7.0 e. 8.6 When using a strongly acidic polystyrene resins (Dowex-50) as the chromatography column to separate amino acids, the separation is mainly a. ion exchange chromatography b. gas-liquid chromatography c. partition chromatography d. liquid-liquid chromatography e. none of the above. The peptide bond has partial character a. hydrogen bond b. double bond c. triple bond d. van der Waals bond e. all of the above. Proteins with two different polypeptide chains are monomeric b. trimeric c. homodimeric d. heterodimeric e. none of the above.

Solution

8. b proline

proline is only amino acid where alpha-amino group is attached directly to the side chain, making the carbon a direct substituent of the side chain.

9. a 3.25

PI = PK1+PK_r/2

2.3+4.2/2

3.25

10. a Ion exchange chromatography

Dowex 50 is a ion exchange resin

11. Peptide bond having partail double bond character

With resonance, the nitrogen is able to donate its lone pair of electrons to the carbonyl carbon and push electrons from the carbonyl double bond towards the oxygen, forming the oxygen anion.

12. heterodimeric

peptide with different polypeptde called heterodimeric