c340 Quiz 6

Chemistry 340 Quiz 6
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Answer with only one choice even if more than one is correct. Use a choice only once.

1-4 are about chymotrypsin. 1-2 are about the reaction; 3-4 are about the active site and mechanism.

1-2. Use these choices: (A) substrate 1; (B) substrate 2; (P) product 1; (R) product 2.

H₂O	the peptide bond next to an aromatic ring
the protein with a new N-terminus	the protein with a new C-terminus

3-4. Use these choices: (D) aspartate; (H) histidine; (O) oxyanion hole; (S) serine;

stabilizes an O⁻ intermediate	forms a covalent bond to the substrate
accepts H⁺ from serine	stabilizes His⁺ with an ionic interaction
donates H⁺ to the substrate	consists of two α–NH groups in the chymotrypsin backbone
accepts H⁺ from H₂O	in the active site but not the catalytic triad

5-8. Use these enzymes:
(Y) chymotrypsin; (X) hexokinase; (E) enolase; (N) carbonic anhydrase.

a hydrolase	has lysine in the active site
a lyase	has glutamate in the active site
a transferase	has aspartate in the active site
uses acid-base catalysis	has Zn²⁺ in the active site
uses covalent catalysis	has Mg²⁺ in the active site
uses metal ion catalysis	does not require a co-factor
uses induced fit catalysis	does not require a coenzyme
has histidine in the active site	requires a co-substrate coenzyme
9. The R conformation of Hb is stabilized when ( O₂ / CO₂ ) binds ( globin / heme ). Underline the correct choice inside each set of parentheses.	10. Draw isoleucine at pH 7.
9. The T conformation of Hb is stabilized when ( O₂ / CO₂ ) binds ( globin / heme ). Underline the correct choice inside each set of parentheses.	10. Draw proline at pH 7.
9. The sequence of amino acid residues is the ( primary / secondary ) level of protein structure. This is stabilized by ( covalent bonds / hydrophobic interactions ). Underline the correct choice inside each set of parentheses.	10. Draw valine at pH 7.
9. The local arrangement of the backbone is the (primary / secondary ) level of protein structure. This is stabilized by (ionic interactions / hydrogen bonds ). Underline the correct choice inside each set of parentheses.	10. Draw leucine at pH 7.