Enzyme Kinetics: Part 2

``` Page 1

Chapter 5 (part 3)
Enzyme Kinetics (cont.)
Page 2

Chapter 5 (part 3)
Enzyme Kinetics (cont.)
Michaelis-Menton
• V
max
• K
m

• K
cat
• K
cat
/K
m

E + S    ES  E + P
k
1
k
-1
k
cat
• Vo = Vmax [S]
Km + [S]

•V
max
•K
m
•k
cat
•k
cat
/K
m
Page 3

Chapter 5 (part 3)
Enzyme Kinetics (cont.)
Michaelis-Menton
• V
max
• K
m

• K
cat
• K
cat
/K
m

E + S    ES  E + P
k
1
k
-1
k
cat
• Vo = Vmax [S]
Km + [S]

•V
max
•K
m
•k
cat
•k
cat
/K
m
How do you get values for V
max
, K
m
and k
cat
?
• Can determine K
m
and V
max
experimentally

• Km can be determined without an absolutely
pure enzyme

• K
cat
values can be determined if V
max
is known
and the absolute concentration of enzyme is
known (V
max
= k
cat
[E
total
]

Page 4

Chapter 5 (part 3)
Enzyme Kinetics (cont.)
Michaelis-Menton
• V
max
• K
m

• K
cat
• K
cat
/K
m

E + S    ES  E + P
k
1
k
-1
k
cat
• Vo = Vmax [S]
Km + [S]

•V
max
•K
m
•k
cat
•k
cat
/K
m
How do you get values for V
max
, K
m
and k
cat
?
• Can determine K
m
and V
max
experimentally

• Km can be determined without an absolutely
pure enzyme

• K
cat
values can be determined if V
max
is known
and the absolute concentration of enzyme is
known (V
max
= k
cat
[E
total
]

Lineweaver-Burke Plots
(double reciprocal plots)
•Plot 1/[S] vs 1/V
o

•L-B equation for straight
line
•X-intercept = -1/Km
•Y-intercept = 1/Vmax
•Easier to extrapolate
values w/ straight line vs
hyperbolic curve

Page 5

Chapter 5 (part 3)
Enzyme Kinetics (cont.)
Michaelis-Menton
• V
max
• K
m

• K
cat
• K
cat
/K
m

E + S    ES  E + P
k
1
k
-1
k
cat
• Vo = Vmax [S]
Km + [S]

•V
max
•K
m
•k
cat
•k
cat
/K
m
How do you get values for V
max
, K
m
and k
cat
?
• Can determine K
m
and V
max
experimentally

• Km can be determined without an absolutely
pure enzyme

• K
cat
values can be determined if V
max
is known
and the absolute concentration of enzyme is
known (V
max
= k
cat
[E
total
]

Lineweaver-Burke Plots
(double reciprocal plots)
•Plot 1/[S] vs 1/V
o

•L-B equation for straight
line
•X-intercept = -1/Km
•Y-intercept = 1/Vmax
•Easier to extrapolate
values w/ straight line vs
hyperbolic curve

B
B
B
B
B
B
B
0
0.05
0.1
0.15
0.2
0.25
0 1 2 3 4 5 6 7 8 9 10
Vo
[S]
[S] Vo
0.5 0.075
0.75 0.09
2 0.152
4 0.196
6 0.21
8 0.214
10 0.23

V max
Km
Km ~ 1.3 mM

Vmax ~ 0.25
```

Biochemistry for MCAT

138 videos|21 docs|4 tests

Biochemistry for MCAT

138 videos|21 docs|4 tests

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