Here you can find out the information about a very important topic of Biochemistry i.e. Enzyme Kinetics. I have elaborated how enzymes kinetics works . The most important equation Michaelis-menten equation, and Burk plot. #enzymes #biochemistry

1. Name – Ankur Kumar
M.Sc. Microbiology
ENZYME
KINETICS
Central University of Haryana

2.  Enzyme Kinetics
Quantitative study of enzyme catalysis.
Measures the reaction rate and the affinity of enzymes for
substrate and inhibitors.
Factors that affect these rates .
“T he st udy of t he rat es of enzyme cat alyzed
react ions and affinit y for subst rat e and inhibit ors is
called Enzyme kinet ics .”

3. Rate of reaction
 Rate of reaction is
proportional to the
products of
concentration of each
reactants.
 K is rate constent.
 F and g are
stoichiometry .

4.  Kinetics of Enzyme catalyzed Reactions
• Rate(velocity) of enzyme catalyzes reaction depends on the
substrate conc.
• Initial velocity (V0) increases linearly with increase in substrate
concentration . [S]
• At high substrate conc., (V0)
becomes virtually independent
of substance conc. and
approaches a maximal
limit.(Vmax)
V0=Vmax

5. .
 In the lower region of curve, showing
first order reaction because rate
proportional to substrate conc .
 In the upper region of curve the
reaction is zero order reaction
because rate of reaction becomes
independent of substrate conc.
 This behaviour is called Saturation
effect.
.
V0=Vmax

6.  Michaelis-menten Approach
• Since enzyme kinetics is a mixture of more than one kinetics and to
represent it overall .
• A particularly useful model for the kinetics of enzyme-catalyzed
reactions was devised in 1913 by Leonor Michaelis and Maud
Menten.
The initial velocity (V0) of an enzyme catalyzed reaction is
determined by two constents (Vmax), ( KM ) and initial conc. of substrate[S]
• Fundamental equation for the enzyme kinetics.

7. KM
• When the rate of the reaction is half its maximum value, the
substrate concentration is equal to the Michaelis constant.
From the Michaelis-menten equation

8. Significance of Km
• Used to measure the [S].or the affinity for the enzyme.
• Small the value of Michaelis menten constent means it will bind
more tightly to enzyme and saturate the enzyme.
Assumptions made -
• [S]>[E]
• The rate of formation of ES is equal to that of breakdown of ES
.[steady state assumption]
• Ignored any back reaction by which EP might form ES .

9.  Lineweaver-Burk plot
• Graphical representation of Lineweaver Burk Equation of enzyme
kinetics.
• From the Michaelis-menten
equation
• Reciprocal the both sides.
• Now eq. has the form of
a straight line
Y m x c

10. .
Y =mx+c
 1/ V0 takes the place of Y coordinate and 1/S takes the place of x
coordinate
 The slope of the line ,(m) is KM /Vmax and the y intercept (c) is 1/Vmax
Significance---
 More accurate determination of
Vmax and also KM .
 Useful in distinguishing between
certain types of enzymatics rxn
mechanism.

11. References
 Principles of Biochemistry, Lehninger 6th ed.
 Biochemistry by Lubert Stryer.
 https://nios.ac.in
 Pathfinder Life science 7th Ed.