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Enzyme
References & Edit History Related Topics
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A multi-panel diagram illustrates how a substrate binds to an enzyme's active site through induced fit, leading to product formation, and shows how non-substrates and allosteric regulators can alter enzyme activity by binding to different sites on the enzyme.
We Couldn't Live Without Enzymes
A person in a white coat pours rennet from a measuring tube into a large copper vat of milk while stirring, part of the cheese making process. Diagram illustrating the lock-and-key model of enzyme action, showing a substrate fitting precisely into the enzyme's active site, while non-substrate shapes do not fit. The enzyme is depicted with a complex outline and labeled binding site, emphasizing specificity. Diagram showing how enzymes catalyze reactions: enzymes bind to substrates, form intermediate complexes, and release products. The lower section details specific mechanisms for acetylcholinesterase, sucrose phosphorylase, and maltose phosphorylase, with labeled steps and components. Two graphs illustrating enzyme action: the left graph shows a Michaelis-Menten curve with reaction velocity rising and leveling off as substrate concentration increases; the right graph compares cooperative curves, with positive cooperativity showing a steep rise, negative cooperativity a gradual rise, and both labeled accordingly.
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Enzyme: References & Edit History

Article Contributors

Primary Contributors

  • The Editors of Encyclopaedia Britannica
    Encyclopaedia Britannica's editors oversee subject areas in which they have extensive knowledge, whether from years of experience gained by working on that content or via study for an advanced degree. They write new content and verify and edit content received from contributors.

Other Encyclopedia Britannica Contributors

Article History

Type Description Contributor Date
Article title updated for style. Nov 11, 2026
Modified link of Web site: National Center for Biotechnology Information - PubMed Central - Enzymes: principles and biotechnological applications. Jul 27, 2026
Add new Web site: Khan Academy - Enzymes and the active site. May 21, 2026
Media added. Apr 17, 2026
Add new Web site: American Chemical Society - Enzymes: Moving at the Speed of Life. Oct 02, 2025
Add new Web site: National Center for Biotechnology Information - PubMed Central - Enzymes: principles and biotechnological applications. Jul 12, 2025
Questions and answers added. Feb 11, 2025
Add new Web site: BMC - BMC Bioinformatics - Anatomy of enzyme channels. Feb 07, 2025
Add new Web site: CORE - Enzymes from extreme environments and their industrial applications. Sep 16, 2024
Add new Web site: Royal Society of Chemistry Publishing - Role of conformational dynamics in the evolution of novel enzyme function. Jul 22, 2024
Add new Web site: The University of Hawaiʻi Pressbooks - Biology - Enzymes. Apr 16, 2024
Add new Web site: Chemistry LibreTexts - Enzymes. Jan 28, 2024
Add new Web site: Open Oregon Educational Resources - Enzymes. Nov 08, 2023
Add new Web site: Royal Society of Biology - Enzymes. Jul 04, 2023
Add new Web site: Cleveland Clinic - Enzymes. Mar 27, 2023
Add new Web site: Chemistry LibreTexts - Enzyme. Aug 19, 2022
Add new Web site: Frontiers - Frontiers in Bioengineering and Biotechnology - Enzymes from Extreme Environments and their Industrial Applications. Apr 10, 2022
Added a photo of rennet being added to milk to make cheese. Aug 06, 2019
Corrected display issue. Aug 06, 2019
Add new Web site: Khan Academy - Enzyme structure and function. Feb 07, 2019
Add new Web site: Healthline - Understanding Digestive Enzymes: Why Are They Important? Feb 07, 2019
Add new Web site: BBC - Bitesize - Enzymes. Feb 07, 2019
Add new Web site: ThoughtCo. - Enzyme Biochemistry - What Enzymes Are and How They Work. May 25, 2018
Corrected display issue. Dec 15, 2017
Added mention of ribozymes. Jun 04, 2015
Added an illustration showing the active site of an enzyme. Jun 04, 2015
Add new Web site: Buzzle.com - Enzyme. Feb 25, 2014
Added new Web site: University of Maryland - Classes of Enzymes. Mar 16, 2009
Added new Web site: Kimball's Biology Pages - Enzymes. Feb 10, 2009
Added new Web site: Rader's Chem4Kids.com - Enzymes. Feb 10, 2009
Added new Web site: Rader's Chem4Kids.Com - Enzyme Regulation. May 05, 2008
Added new Web site: Rader's Chem4Kids.Com - Enzymes. May 05, 2008
Article revised and updated. Mar 26, 2008
Added new Web site: Clinton Community College - Enzymes. Apr 27, 2007
Added new Web site: Royal Society of Chemistry - Chemistry for Biologists - Enzymes. Apr 27, 2007
Added new Web site: HowStuffWorks - Enzymes.
  • Gaurav Shukla
 Feb 01, 2007
Added new Web site: Western Yeast - How Enzymes Work.
  • Gaurav Shukla
 Jan 28, 2007
Added new Web site: Allonhealth.com - Digestive Enzymes.
  • Gaurav Shukla
 Jan 28, 2007
Added new Web site: Gondar Design Biology - Enzymes.
  • Gaurav Shukla
 Jan 25, 2007
Article added to new online database. Jul 20, 1998
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