Different plots for Determination of km and vmax

1. Different Plots for
Determination of Km and
Vmax
SUBMITTED BY: Amir sohil
SUBMITTED TO: Bharat Bhusan Sir

2. Vmax
Vmax is the reaction rate when the
enzyme is fully saturated by substrate,
indicating that all the binding sites are
being constantly reoccupied.
Km
Km is a value of substrate concentration at
half maximal velocity

4. Michaelis-Menten Equation
Michaelis –Mentum kinetics is one of the
simplest and best known model of enzyme
kinetics.
This model explain how an enzyme can
cause kinetic rate enhancement of a
reaction and why the rate of reaction
depends on the concentration of enzyme
present.

6. According to this model the enzyme
reversibly bind with substrate to form an ES
complex that subsequently yield product.

7. The mechanism of enzyme catalyzed
reactions is studied by making kinetic
measurements on enzyme substrate
reaction system
The simple kinetic model os obtained,
when plotting the rate of catalysis,V
(reaction velocity),V/S the substrate
concentration [S]

8. From this equation, the reaction velocity,V
can be expressed as
.

9. Lineweaver-Burk Plot
 The Lineweaver-Burk plot is a
representation of the Lineweaver-Burk
Equation of Enzyme kinetics,described by
Lineweaver and Dean Burk in 1934.

11. 
Taking the reciprocal of this equation
gives

12. This plot was widely used to determine Km
and Vmax, before the wide availability of
powerful computers and non-linear
regression Software.

13. Eadie-Hofstee and Hanes Plot
The Lineweaver-Burk plot has been criticized
on several grounds
Firstly the extrapolation across the 1/Vo axis
determine _1/Km sometimes reaches the
of graph paper before reaching 1/[S] axis
Secondly, it is said to give undue weight to
measurements made at low concentration.

14. Eadie-Hofstee Plot

15. The Eadie-Hofstee plot takes as its
starting point the Lineweaver-Burk
equation.Both sides of the equation are
multiplied by the factor Vo V max :

16. The Hanes plot (devised by Charles
Hanes) similarly starts with the Lineweaver-
Burk equationwhich in this instance is
multiplied throughout by [S]

18. Eisenthal and Cornis Bowden Plot
In view of the difficulties in obtaining reliable
estimates of Km and V max , even with
the aid of statistical analysis, from the plots
discussed above, Robert Eisenthal and
Athel Comish-Bowden (1974) suggested a
different approach, though one still based
on the Michaelis-Menten equation (7.12). The
reciprocal form of this equation, at
constant [E0], gives

20. 
Therefore, at constant v0 and [S0], a plot
of V max against Km is linear.

21. References
Palmer Trevor,Bonnner Philip
Enzymes second edition
Gupta N.S Biochemistry