What is enzyme? How enzyme catalyze the reaction Enzyme kinetics History Enzyme kinetic equation Michaelis-menten equation Michaelis-menten curve Michaelis-menten equation derivation Reversible inhibition Two substrate reaction Conclusion References

1. ENZYME KINETICS
By
KAUSHAL KUMAR SAHU
Assistant Professor (Ad Hoc)
Department of Biotechnology
Govt. Digvijay Autonomous P. G. College
Raj-Nandgaon ( C. G. )

2. -:SYNOPSIS:-
• What is enzyme?
• How enzyme catalyze the reaction
• Enzyme kinetics
• History
• Enzyme kinetic equation
• Michaelis-menten equation
• Michaelis-menten curve
• Michaelis-menten equation derivation
• Reversible inhibition
• Two substrate reaction
• Conclusion
• References

3. -:ENZYME:-
• Enzyme is a complex protein.
• Apo enzyme + co-enz/co-factor/prosthetic grp
Holoenzyme
• The protein part such an enzyme is called Apo enzyme.
• A complex organic molecule called Coenzyme.
• A coenzyme or metal ion that is very tightly covelently
bound to the enzyme protein called a Prosthetic group.
• A complete,catalytically active enzyme bound with
coenzyme called Holoenzyme.

4. • S P (10 min)
• S P(5 min)
(catalyst)
• Any substance that increase the rate of
reaction witout itself being consumed called
catalyst.
• Catalyst used in biological reaction is called
enzyme.

5. -:HOW ENZYME CATALYZE THE
REACTION:-
• When substrate bind with enzyme, energy is release called binding
energy.this binding energy decrease the activation.

6. -:ENZYME KINETICS:-
 Enzyme kinetics is the investigation of how
enzyme bind substrates and turn them into
product.

7. -:HISTORY:-
• In 1902 Victor Henri proposed a quantitative
theory of enzyme kinetics but his experimental
data were not useful.
• In 1909 Leonor Michaelis & his Canadian postdoc
Maud Menten repeated Henri’s experiments and
confirm his equation which is referred to as
Michaelis-Menten kinetics equation.

8. -:ENZYME KINETIC EQUATION:-

9. -:MICHAELIS-MENTEN EQUATION:-
Km=one half of the maximal
velocity, and unit of
concentration & michaelis
constant.

10. -:MICHAELIS-MENTEN EQUATION
CURVE:-
• Effect of cons. Of substrate on the velocity of
reaction-

11. -:MICHAELIS-MENTEN EQUATION
DERIVATION:-
• E+S  ES  EP E+P (1)
• (2)
• Michaelis and Menten derived this equation starting from their basic
hypothesis that the rate-limiting step in enzymatic reactions is the
breakdown of the ES complex to product and free enzme. The important
terms are [S], Vo, Vmax, and a constant called the Michaelis constant.
•
• (3)

12. • If reverse reaction P to S (denoted by K_2)
can be ignored.
(4)
• Vo is determined by the breakdown of ES to
form product,which is determine by ES:-
Vo = K2 (ES) (5)
E + S ES E + P
k1 k2
k-1

13. • Rate of ES formation = k1([ET] - [ES])[S]
(where [ET] is total concentration of
enzyme E and k-2 is considered
neglible)
• Rate of ES breakdown to product = k-
1[ES] + k2[ES]

14. k1([ET] - [ES])[S] = k-1[ES] + k2[ES] (6)
Rate of formation of ES is equal to the rate
of its breakdown. This is called “Steady-
state assumption.”

15. • k1[ET][S]-k1[ES][S]=[k-1 + k2] [ES] (7)
Left side is multiplied out and the right side
simplified given.

16. • k1[ET][S]=(k1 [S]+ k-1 + k2 )[ES] (8)
• We solve the equation for[ES]
k1[ET][S]
[ES]= (9)
k1 [S]+ k-1 + k2

17. [ET][S]
• [ES]= (10)
[S]+ (k-1 + k2 )/ k1

18. [ET][S]
• [ES] = (11)
Km + [S]
The term (k-1 + k2 )/ k1 is defined as the
Michaelis constant, Km.

19. k2 [ET][S]
• Vo = (12)
Km + [S]
Here Vo = k2 [ ES ] in the equation 5.

20. • (13)
• Maximum velocity occurs when the enzyme is
saturated(that is [ES]= [ ET ])Vmax can be
defined as k2 (ET ).This is Michaelis-
Menten equation.

21. Vmax Vmax [S]
= (14)
2 Km + [S]
Vo is exactly one-half Vmax .

22. • 1 [S]
= (15)
2 Km + [S]
on dividing by Vmax .

23.  solving for Km we get Km +S=2S
or
• Km =[S], when Vo = 1/2 Vmax.

24. -:REVERSIBLE INHIBITION:-
• COMPETITIVE INHIBITION:-

25. • UNCOMPETITIVE INHIBITION:-

26. • MIXED/NON COMPETITIVE INHIBITION:-

27. -:TWO SUBSTRATE REACTION:-

28. CONCLUSION
• enzyme kinetics is the study of how biological
catalyst increase the reaction.
• In enzyme kinetics when target molecules bind
to an enzymes active site and are transformed
into product through series of step .

29. REFERENCES
• PRINCIPLE OF BIOCHEMISTRY:- NELSON & COX
5TH Edition.
• www.wikipedia.com .