782 / 912
774 Chapter 23
Copyright © 2017 Pearson Education, Inc.
Chapter 23 Practice Test
1.
What two coenzymes put carboxyl groups on their substrates?
2.
What are the three one-carbon groups that tetrahydrofolate coenzymes put on their substrates?
3.
Show the mechanism for NADPH reducing its substrate.
4.
Draw the structure of the compound obtained when the following amino acid undergoes transamination:
CH
3
CH
2
CHCH
CH
3
NH
3
+
_
O
C
O
5.
What is the first step in the reaction of the substrate with coenzyme
B
12
in an enzyme-catalyzed reaction
that requires coenzyme
B
12
?
6.
What coenzyme is required for each of the following enzyme-catalyzed reactions?
enzyme
enzyme
COO
_
CH
3
CH
2
SCoA
C
O
CH
2
CH
2
SCoA
C
O
CH
3
CH SCoA
C
O
COO
_
7.
Show the enzyme-catalyzed reaction that requires vitamin
KH
2
as a coenzyme.
8.
Draw the product of the enzyme-catalyzed reaction that requires biotin and whose substrate is acetyl-CoA.
9.
a.
Other than the substrate, enzyme, and coenzyme, what three additional reagents are needed by a reac-
tion that requires biotin as a coenzyme?
b.
What is the function of each of these reagents?
10.
What is the function of FAD in the pyruvate dehydrogenase system?
11.
Draw the structures of the two products obtained from the following transamination reaction:
CH
2
CH
−
−
+
NH
3
HO
+
transamination
O
−
O
O CH
2
CH
2
C
O
C
O
C
O
C
O