Sign In

Enzyme kinetics studies the rates of biochemical reactions. Scientists monitor the reaction rates for a particular enzymatic reaction at various substrate concentrations. Additional trials with inhibitors or other molecules that affect the reaction rate may also be performed.

The experimenter can then plot the initial reaction rate or velocity (Vo) of a given trial against the substrate concentration ([S]) to obtain a graph of the reaction properties. For many enzymatic reactions involving a single substrate, this data fits the Michaelis-Menten equation, an equation derived by Leonor Michaelis and Maud Menten.

Eq1

The equation estimates the maximum velocity (Vmax) and the Michaelis constant (KM) for the enzyme being studied and is based on the following assumptions:

  1. No product is present at the start of the reaction.
  2. The rate of enzyme-substrate complex formation equals the rate of dissociation and breakdown into products.
  3. The enzyme concentration is minimal compared to the substrate concentration.
  4. Only the initial reaction rates are measured.
  5. The enzyme is present either in the free form or in the enzyme-substrate complex.

Different rearrangements of the Michaelis-Menten equation, such as the Lineweaver-Burke, Eadie-Hofsteot, and Hanes-Woolf plots, are alternate ways to graph kinetic parameters. The Lineweaver-Burke or double reciprocal plot is often used to estimate the KM and the Vmax. The plot uses the reciprocals values of the x and y-axis from the Michaelis-Menten plot. Mathematically, the y-intercept equals 1/Vmax, and the x-intercept equals −1/KM.

The Lineweaver-Burke plot can be used to visually differentiate between inhibitor types – competitive, non-competitive, and uncompetitive. Different rearrangements of the Michaelis-Menten equation, such as the Eadie-Hofstee and Hanes-Woolf plots, are also used to determine kinetic parameters.

Tags
Enzyme KineticsReaction RateSubstrate ConcentrationMichaelis Menten EquationVmaxKMLineweaver Burke PlotEadie Hofstee PlotHanes Woolf PlotEnzyme substrate ComplexInhibitor TypesCompetitive InhibitionNon competitive InhibitionUncompetitive Inhibition

From Chapter 3:

article

Now Playing

3.13 : Introduction to Enzyme Kinetics

Energy and Catalysis

19.2K Views

article

3.1 : القانون الأول للديناميكا الحرارية

Energy and Catalysis

5.2K Views

article

3.2 : القانون الثاني للديناميكا الحرارية

Energy and Catalysis

4.8K Views

article

3.3 : المحتوى الحراري داخل الخلية

Energy and Catalysis

5.6K Views

article

3.4 : الانتروبيا داخل الخلية

Energy and Catalysis

10.1K Views

article

3.5 : مقدمة في الطاقة الحرة

Energy and Catalysis

7.9K Views

article

3.6 : التفاعلات الداخلية والطاردة للطاقة في الخلية

Energy and Catalysis

13.9K Views

article

3.7 : ثابت ربط التوازن وقوة الربط

Energy and Catalysis

8.9K Views

article

3.8 : الطاقة الحرة والتوازن

Energy and Catalysis

5.9K Views

article

3.9 : عدم التوازن في الخلية

Energy and Catalysis

4.0K Views

article

3.10 : أكسدة وتقليل الجزيئات العضوية

Energy and Catalysis

5.7K Views

article

3.11 : مقدمة في الإنزيمات

Energy and Catalysis

16.4K Views

article

3.12 : الإنزيمات وطاقة التنشيط

Energy and Catalysis

11.2K Views

article

3.14 : رقم الدوران والكفاءة الحفازة

Energy and Catalysis

9.6K Views

article

3.15 : إنزيمات مثالية تحفيزيا

Energy and Catalysis

3.8K Views

See More

JoVE Logo

Privacy

Terms of Use

Policies

Research

Education

ABOUT JoVE

Copyright © 2025 MyJoVE Corporation. All rights reserved