Download Ch. 6 Diagrams

Ch. 6 Metabolism
Diagrams
Figure 8.UN01
Enzyme 2
Enzyme 1
A
Reaction 1
Starting
molecule
Enzyme 3
D
C
B
Reaction 2
Reaction 3
Product
Animation: Energy Concepts
Right-click slide / select “Play”
© 2011 Pearson Education, Inc.
Figure 8.3
Heat
Chemical
energy
(a) First law of thermodynamics
(b) Second law of thermodynamics
(a) Exergonic reaction: energy released, spontaneous
Reactants
Free energy
Amount of
energy
released
(G  0)
Energy
Products
Progress of the reaction
(b) Endergonic reaction: energy required, nonspontaneous
Products
Free energy
Figure 8.6
Amount of
energy
required
(G  0)
Energy
Reactants
Progress of the reaction
Figure 8.8
Adenine
Phosphate groups
Ribose
(a) The structure of ATP
Adenosine triphosphate (ATP)
Energy
Inorganic
phosphate
Adenosine diphosphate (ADP)
(b) The hydrolysis of ATP
Figure 8.9
(a) Glutamic acid
conversion
to glutamine
NH3
Glutamic
acid
(b) Conversion
reaction
coupled
with ATP
hydrolysis
NH2
Glu
Glu
GGlu = +3.4 kcal/mol
Glutamine
Ammonia
NH3
P
1
Glu
ATP
Glu
2
ADP
Glu
Phosphorylated
intermediate
Glutamic
acid
NH2
Glutamine
GGlu = +3.4 kcal/mol
(c) Free-energy
change for
coupled
reaction
NH3
Glu
GGlu = +3.4 kcal/mol
+ GATP = 7.3 kcal/mol
Net G = 3.9 kcal/mol
ATP
NH2
Glu
GATP = 7.3 kcal/mol
ADP
Pi
ADP
Pi
Figure 8.10
Transport protein
Solute
ATP
ADP
P
Pi
Pi
Solute transported
(a) Transport work: ATP phosphorylates transport proteins.
Cytoskeletal track
Vesicle
ATP
ADP
ATP
Motor protein
Protein and
vesicle moved
(b) Mechanical work: ATP binds noncovalently to motor
proteins and then is hydrolyzed.
Pi
Figure 8.11
ATP
Energy from
catabolism (exergonic,
energy-releasing
processes)
ADP
H2O
Pi
Energy for cellular
work (endergonic,
energy-consuming
processes)
Figure 8.UN02
Sucrase
Sucrose
(C12H22O11)
Glucose
(C6H12O6)
Fructose
(C6H12O6)
Figure 8.12
A
B
C
D
Free energy
Transition state
A
B
C
D
EA
Reactants
A
B
G  O
C
D
Products
Progress of the reaction
Animation: How Enzymes Work
Right-click slide / select “Play”
© 2011 Pearson Education, Inc.
Figure 8.13
Free energy
Course of
reaction
without
enzyme
EA
without
enzyme
EA with
enzyme
is lower
Reactants
G is unaffected
by enzyme
Course of
reaction
with enzyme
Products
Progress of the reaction
Figure 8.14
Substrate
Active site
Enzyme
(a)
Enzyme-substrate
complex
(b)
Figure 8.15-3
1 Substrates enter active site.
2 Substrates are held
in active site by weak
interactions.
Substrates
Enzyme-substrate
complex
3 Active site can
lower EA and speed
up a reaction.
6 Active
site is
available
for two new
substrate
molecules.
Enzyme
5 Products are
released.
4 Substrates are
converted to
products.
Products
Figure 8.16
Rate of reaction
Optimal temperature for
Optimal temperature for
typical human enzyme (37°C) enzyme of thermophilic
(heat-tolerant)
bacteria (77°C)
60
80
Temperature (°C)
(a) Optimal temperature for two enzymes
0
20
40
Rate of reaction
Optimal pH for pepsin
(stomach
enzyme)
0
5
pH
(b) Optimal pH for two enzymes
1
2
3
4
120
100
Optimal pH for trypsin
(intestinal
enzyme)
6
7
8
9
10
Figure 8.17
(a) Normal binding
(b) Competitive inhibition
(c) Noncompetitive
inhibition
Substrate
Active
site
Competitive
inhibitor
Enzyme
Noncompetitive
inhibitor
Figure 8.19
(b) Cooperativity: another type of allosteric activation
(a) Allosteric activators and inhibitors
Allosteric enzyme
with four subunits
Active site
(one of four)
Regulatory
site (one
of four)
Substrate
Activator
Inactive form
Stabilized active form
Active form
Oscillation
Nonfunctional
active site
Inactive form
Inhibitor
Stabilized inactive
form
Stabilized active
form
Figure 8.20
EXPERIMENT
Caspase 1
Active
site
Substrate
SH
Active form can
bind substrate
SH
Known active form
SH
Allosteric
binding site
Known inactive form
Allosteric
inhibitor
Hypothesis: allosteric
inhibitor locks enzyme
in inactive form
RESULTS
Caspase 1
Inhibitor
Active form
Allosterically
inhibited form
Inactive form
Figure 8.21
Active site
available
Isoleucine
used up by
cell
Active site of
Feedback
enzyme 1 is
inhibition
no longer able
to catalyze the
conversion
of threonine to
intermediate A;
pathway is
switched off. Isoleucine
binds to
allosteric
site.
Initial
substrate
(threonine)
Threonine
in active site
Enzyme 1
(threonine
deaminase)
Intermediate A
Enzyme 2
Intermediate B
Enzyme 3
Intermediate C
Enzyme 4
Intermediate D
Enzyme 5
End product
(isoleucine)