Enzyme
substrate
complex
kinetics
→
study
of
the
rate
of
reactant
compounds
,
-
-
y
-
-
-
-
-
Mita
's
"
/
COBB
.
-
substrate
§
Rate
of
enzymatic
reaction
Is
affected
by
:
£
enzyme
-1
substrate
Tv
"
-
-
-
"
¥+1929m
Act
'
"e_N
Site
/
enzyme
+
product
Enzyme
,
Substrate
,
Effectors
and
Temperature
¥
-
Gaggi
_⑨↑,j☐a
En!g*
C)
Ki
gress
-
E-
+
SEES
Reasons
for
studying
:
K
,
Enzyme
(E)
combines
with
its
substrate
to
form
an
enzyme
substrate
(
ES
)
complex
in
a
fast
reversible
step
:
Quantitative
description
of
biocatalysts
,
Determines
ES
complex
then
breaks
down
/
na
slower
second
step
-10
yield
the
-
free
enzyme
and
the
reaction
product
CP
)
Kz
Order
of
binding
of
substrates
.
Elucidate
acid-base
EsEtP
Effect
Of
Substrate
Concentration
On
Reaction
Rate
kz
catalysis
.
Understand
catalytic
mechanism
,
find
A.
B.
-
-
-
-
-1m¥
-
=
-
-
effective
inhibitors
and
understand
regulation
of
activity
§É
"
Maximum
Velocity
(
Vmax
)
É"
÷÷±÷÷÷÷÷
¥
.
.
Substrate
concentration
CS
)
,
(
mM
)
c.
E-
_É%E¥¥
?
i
É
-
T.tl/ ma x
km
[
s
]cmM
)
Time
§É,_
;
I
[
S
]=
substrate
concentration
'
Vmax
-_
maximum
velocity
km
[
SJCMM
)
i
vo=im+ia
/
velocity
Michaelis
-
Menten
Equation
Km
-
_
Michaels
constant
km
[
STCMM
)
Rate-limiting
step
in
enzymatic
reactions
Is
the
breakdown
of
ES
step
I
→
Rate
of
formation
and
breakdown
of
ES
;
governed
complex
-10
product
and
free
enzyme
by
rate
constants
↓
K
,
(
[
F-
+
]
-
[
ES
]
)[
S
]
↳
K
-
I
[
Es
]
-114
>
[
ES
]
Early
reaction
→
concentration
of
product
is
negligible
;
-
simplifying
assumption
made
step
>
→
Rate
of
formation
and
breakdown
's
equal
>
steady-state
(
p
-7s
can
be
ignored
)
ASSUMPTION
K
,
(
[
E-
+
]
-
[
ES
]
)[
57=14
_
,
[
ES
]
-1142
[
ES
]
KI
>
turnover
#
show
many
substrate
molecules
one
Reaction
reduces
-10
:
K
,
enzyme
molecule
can
convert
per
C-
+
SEES
_>E+P
Step
3
→
Algebraically
solve
for
[
ES
]
and
define
Micheal
's
constant
,
kmas
(
Kitkz
)
/
ki
second
K
,
K
,
[
E
,
]
[
5
]
-
k
,
[
ESTES
]
=
(
K
.
,
-114
,
)[
ES
]
→
K
,[E+][
S
]
:(
K
,
[
s
]
-1K
,
,
-1K
,
)
[
ES
]
↓
to
determined
by
breakdown
of
Esto
form
product
as
]=Y
.im?Y-s,--E5---:?.?-.ia.L-cess=I#--?E+?a.
(
determined
by
ES
;Vo=k z[
ES
]
)
step
4
→
Express
llointermsof
[
ES
]
and
simplify
Not
easily
measured
;
alternative
expression
[
Eg
]
=
[
E+
]
[
S
]
"
0=142
[
Es
]
Yma×=K z[
Et
]
yo
=
Vma÷{§
}
]
→
"
◦
=
"
2
]
→
[
Et
]
→
Represents
the
total
enzyme
concentration
(
sum
of
free
and
substrate
bound
enzyme
introduced
)
Kinetic
Parameters
Free
/
Unbound
enzyme
[
E)
=
[
Et
]
-
[
ES
]
Nonlinear
Michaelis
-
Menten
plot
→
calculates
km
+
Vmax
[
5)
Is
>
[
Et
]
;
amount
of
substrate
bound
by
the
enzyme
is
negligible
compared
Max
velocity
(
Vmax
)
Enzyme
Efficiency
to
the
total
[
S
]
Limited
by
speolfity
:Kca+
/
K.ms?Kca+=Kz
§¥É
"
"
"
"
"
"
"
"
"
"
"
"
"
"
"
"
"
→
"
"
"
"
"
"
"
"
"
"
"
"
"
"
"
"
"
"
°
"
Diffusion
from
active
site
limits
maximum
value
for
specificity
Gain
efficiency
by
having
high
velocity
/
affinity
for
substrate
(
Vous
[
s
]
)
;
approaches
Vmax
at
high
[
s
]
I
catalase
us
acetylcholinesterase
"
"
⇐
¥×
cannot
accurately
determine
Vmax
/
km
1
'
from
nonlinear
graphs
Enzymes
:
Keat
/
Km
close
-10
Diffusion
-
controlled
Limit
Clio
-1010
'M
's
-5
K"
M
[
SJLMM
)
kmcs
-1
,
kcatlkm
Derived
by
the
reciprocal
of
both
sides
Enzyme
substrate
Kcatcs
"
)
(
M
-151
)
+
Acetylcholine sterase
Acetylcholine
1.4×104
9×10-5
1.6×108
I
/
V0
=
Km
/
Vmax
[
S
]
-11
/
Vmax
coz
1×106
1.2×10-2
8.3×107
Carbonic
anhydrase
Hoo
,
-
4×105
2.6×10-2
1.5×107
¥
Catalase
1-1202
4×10
>
1.1×100
4×10
?
I
/
Vous
l
/
[
S
]
=
straight
line
Crotonase
Crotonyl
-
CoA
5.7×103
2×10-5
2.8×108
£
-
(
Fumarate
8×102
5×10-6
1.6×108
"
'
Mara
"
Malate
9×102
2.5×10-5
3.6×107
Y
Intercept
-71/11
Max
B-
Lactamase
Benzyl
penicillin
2.0×103
2×10-5
1×108
✗
Intercept
-3
-11km
