Download Chapter 22 - UCSB CLAS

CLAS – Chem 109C – Ch 22
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1. Answer the following:
a. Which amino acid(s) is achiral?
b. Are naturally occurring amino acids D or L?
2. Draw the following amino acids at pH = 0, 5, and 13.
a. Valine
b. Glutamate
c. Lysine
3. Calculate the pI of the following amino acids.
a. Phenylalanine
b. Histidine
c. Aspartic Acid
4. What is the net charge of the following amino acids at the designated pHs?
a. Serine at pH = 4
b. Arginine at pH = 9
c. Glutamic acid at pH = 5
5. Which amino acids are the most polar and nonpolar?
6. Thin layer chromatography of a solution of threonine, valine, lysine, alanine and serine yielded the following;
determine which amino acid goes with each spot?
7. Gel electrophoresis of a solution of histidine, tyrosine, lysine, aspartate and glutamic acid yielded the following
determine which amino acid goes with each spot?
anode
c
cathode
a
8. Show how valine can be synthesized via…
a. HVZ
b. Reductive amination
c. N-Phthalimidomalonic ester synthesis
d. Strecker Sythesis
9. Explain kinetic resolution.
10. Draw the met-ile-tyr-asn-his at pH = 7
11. Provide 2 ways the following peptide can be synthesized:
ala-gly-ser
12. Distinguish between primary, secondary, tertiary and quaternary structures of peptides and proteins.
13. Descibe denaturation and give examples of possible causes for denaturation.
14. Show the cleavage sites on the following peptide if introduced to each of the following reagents:
a. Carboxypeptidase A ⇒ ala-gly-phe-met-ser-lys-tyr-asn-glu-arg-pro-met-leu-his
b. Edman’s ⇒ ala-gly-phe-met-ser-lys-tyr-asn-glu-arg-pro-met-leu-his
c. Cyanogen bromide ⇒ ala-gly-phe-met-ser-lys-tyr-asn-glu-arg-pro-met-leu-his
d. Trypsin ⇒ ala-gly-phe-met-ser-lys-tyr-asn-glu-arg-pro-met-leu-his
e. Chymotrypsin ⇒ ala-gly-phe-met-ser-lys-tyr-asn-glu-arg-pro-met-leu-his