Q33. Lineweaver–Burk plot is a plot of
Introduction
In enzyme kinetics, graphical methods are used to determine important constants
like Vmax and Km. The
Lineweaver–Burk plot, also known as the double reciprocal plot,
converts the curved Michaelis–Menten graph into a straight line for easier calculation of
kinetic parameters.
Step 1: Michaelis–Menten Equation
v0 = (Vmax[S]) / (Km + [S])
Where:
v0 = initial velocity
Vmax = maximum velocity
Km = Michaelis constant
[S] = substrate concentration
Step 2: Take Reciprocal
1/v0 = (Km + [S]) / (Vmax[S])
Step 3: Rearranging
1/v0 = (Km/Vmax) × (1/[S]) + 1/Vmax
Step 4: Compare with Straight Line Equation
y = mx + c
- y → 1/v0
- x → 1/[S]
- Slope → Km/Vmax
- Intercept → 1/Vmax
Therefore, Lineweaver–Burk plot is 1/v0 vs 1/[S].
Explanation of Each Option
(A) 1/v0 vs 1/[S]
Produces a straight line and helps calculate kinetic parameters → Correct
(B) v0 vs [S]
Hyperbolic Michaelis–Menten curve, not linear → Incorrect
(C) v0 vs 1/[S]
Does not give linear relationship → Incorrect
(D) 1/v0 vs [S]
Not derived from the equation → Incorrect
Graph Properties
- Y-axis → 1/v0
- X-axis → 1/[S]
- Straight line obtained
- Slope → Km/Vmax
- Y-intercept → 1/Vmax
- X-intercept → −1/Km
Final Answer
(A) 1/v0 vs 1/[S]
Quick Exam Shortcut
Remember: Lineweaver–Burk = Double Reciprocal Plot
So both axes contain reciprocals.
Key Takeaways
- Linear form of Michaelis–Menten equation
- Helps determine Vmax and Km
- Straight-line graph
- Always reciprocal vs reciprocal