Michaelis Menten Formula Calculator

Michaelis-Menten Equation:

\[ Km = [S] \left( \frac{V_{max}}{v} - 1 \right) \]

Michaelis Constant (K_m):

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1. What is the Michaelis-Menten Equation?

The Michaelis-Menten equation describes the rate of enzymatic reactions by relating reaction velocity to substrate concentration. The Michaelis constant (K_m) represents the substrate concentration at which the reaction velocity is half of V_max.

2. How Does the Calculator Work?

The calculator uses the Michaelis-Menten equation rearranged to solve for K_m:

\[ Km = [S] \left( \frac{V_{max}}{v} - 1 \right) \]

Where:

\( Km \) — Michaelis constant (mM)
\( [S] \) — Substrate concentration (mM)
\( V_{max} \) — Maximum reaction velocity (μM/min)
\( v \) — Measured reaction velocity (μM/min)

Explanation: The equation calculates the substrate concentration at which the enzyme operates at half its maximum velocity, indicating the enzyme's affinity for the substrate.

3. Importance of Km Calculation

Details: K_m is a key parameter in enzyme kinetics that indicates the affinity of an enzyme for its substrate. Lower K_m values indicate higher affinity.

4. Using the Calculator

Tips: Enter substrate concentration in mM, V_max and reaction velocity in μM/min. All values must be positive and reaction velocity must be less than V_max.

5. Frequently Asked Questions (FAQ)

Q1: What does a high Km value indicate?
A: A high K_m indicates low enzyme-substrate affinity, meaning the enzyme requires higher substrate concentration to reach half of V_max.

Q2: How is Km experimentally determined?
A: K_m is typically determined by measuring initial reaction rates at various substrate concentrations and fitting the data to the Michaelis-Menten equation.

Q3: What factors affect Km?
A: K_m is affected by temperature, pH, enzyme modifications, and the presence of inhibitors or activators.

Q4: What's the relationship between Km and enzyme efficiency?
A: While K_m measures affinity, enzyme efficiency is better represented by k_cat/K_m, which incorporates both affinity and catalytic rate.

Q5: Can Km be used to compare different enzymes?
A: Yes, K_m values allow comparison of different enzymes' affinities for the same substrate or one enzyme's affinity for different substrates.