Dissociation Constant In Competitive Inhibition Given Maximum Rate Of System Calculator

Formula Used:

\[ K_i = \frac{I}{\left(\frac{\left(\frac{V_{max} \times S}{V_0} - S\right)}{K_M} - 1\right)} \]

Inhibitor Concentration (I):

mol/m³

Maximum Rate (Vmax):

mol/m³·s

Substrate Concentration (S):

mol/m³

Initial Reaction Rate (V₀):

mol/m³·s

Michaelis Constant (K_M):

mol/m³

Enzyme Inhibitor Dissociation Constant (K_i):

Unit Converter ▲

Unit Converter ▼

From:	To:

1. What is Enzyme Inhibitor Dissociation Constant?

The Enzyme Inhibitor Dissociation Constant (K_i) is a measure of the affinity between an enzyme and its inhibitor. It represents the concentration of inhibitor required to occupy half of the enzyme's active sites and is measured by titrating inhibitor into an enzyme solution while monitoring heat changes.

2. How Does the Calculator Work?

The calculator uses the formula for competitive inhibition:

\[ K_i = \frac{I}{\left(\frac{\left(\frac{V_{max} \times S}{V_0} - S\right)}{K_M} - 1\right)} \]

Where:

\( K_i \) — Enzyme Inhibitor Dissociation Constant (mol/m³)
\( I \) — Inhibitor Concentration (mol/m³)
\( V_{max} \) — Maximum Rate (mol/m³·s)
\( S \) — Substrate Concentration (mol/m³)
\( V_0 \) — Initial Reaction Rate (mol/m³·s)
\( K_M \) — Michaelis Constant (mol/m³)

Explanation: This formula calculates the dissociation constant for competitive inhibition, where the inhibitor competes with the substrate for the enzyme's active site.

3. Importance of Dissociation Constant Calculation

Details: The dissociation constant is crucial for understanding enzyme-inhibitor interactions, drug design, and determining the potency of enzyme inhibitors in biochemical and pharmacological studies.

4. Using the Calculator

Tips: Enter all values in appropriate units (mol/m³ for concentrations, mol/m³·s for rates). Ensure all values are positive and the denominator doesn't approach zero to avoid undefined results.

5. Frequently Asked Questions (FAQ)

Q1: What does a lower K_i value indicate?
A: A lower K_i value indicates stronger binding affinity between the enzyme and inhibitor, meaning the inhibitor is more potent.

Q2: How does competitive inhibition differ from other types?
A: In competitive inhibition, the inhibitor competes directly with the substrate for the active site, increasing the apparent K_M without affecting V_max.

Q3: What are typical K_i values for effective inhibitors?
A: Effective enzyme inhibitors typically have K_i values in the nanomolar to micromolar range, indicating strong binding affinity.

Q4: Can this calculator be used for non-competitive inhibition?
A: No, this specific formula is designed for competitive inhibition. Different equations are used for non-competitive and uncompetitive inhibition.

Q5: What experimental methods measure K_i?
A: K_i can be measured through various methods including isothermal titration calorimetry, enzyme kinetics studies, and spectroscopic methods.