Physical Chemistry 3: — Chemical Kinetics — - Christian-Albrechts ...

10.1 Kinetics of enzyme catalyzed reactions (homogeneous catalysis) 216
Resulting rate expression:
y
= [P] = 2 [ES] (10.20)
1 2 [E]
=
0
[S] 0
(10.21)
1 [S] 0
+ −1 + 2
2 [E]
=
0
1+ (10.22)
−1 + 2
1 [S] 0
=
with the Michaelis-Menten constant
2 [E] 0
1+ [S] 0
(10.23)
= −1 + 2
1
(10.24)
Limiting cases:
(1) [S] 0
→∞y
[S] 0
¿ 1: y
= [P]
= 2 [E] 0
(10.25)
(2) [S] 0
→ 0 y
[S] 0
À 1: y
= [P]
= 2 [E] 0
[S] 0
(10.26)
Determination of 2 and from a Lineweaver-Burk plot (Fig. 10.2):
1
= 1 +
1
(10.27)
2 [E] 0
2 [E] 0
[S] 0
⇒ Aplotof −1 vs. [S] −1 0
should give a straight line with intercept ( 2 [E] 0
) −1 and
slope 2 [E] 0
. y
slope
intercept = = −1 + 2
(10.28)
1