active site


: a region on the surface of an enzyme whose shape permits binding only of a specific molecular substrate that then undergoes catalysis

Examples of active site in a Sentence

Recent Examples on the Web Despite 25 years of active site remediation, and evidence that the concentration of contaminants is declining, significant impacts to the soil and groundwater remain. Staff Reports, Hartford Courant, 4 Jan. 2024 There were fewer than 50 active sites in August, shortly after the ban took effect. Blake Nelson, San Diego Union-Tribune, 15 Jan. 2024 Advertisement Carnegie’s agreement with the U.S. Forest Service stipulates that the observatory must remain an active site for research, astronomy or education — or be dismantled down to its last historic bolt. Corinne Purtill, Los Angeles Times, 3 Oct. 2023 There were no longer crowds outside the border wall gates marked 40 and 42 — some of the most active sites of migrant crossings recently. Nick Miroff, Washington Post, 12 May 2023 Researchers believe this was all an active site roughly 7,000 years ago. Tim Newcomb, Popular Mechanics, 11 May 2023 The vineyard is an active site year-round, with pruning starting in January when vines are dormant (in the northern hemisphere) in anticipation of warmer weather and bud break in the early spring. Mike Desimone and Jeff Jenssen, Robb Report, 5 Jan. 2023 The fire was on private property owned by WR Grace, which isn’t an active site and went out of business, Arnum said. Matt Yan,, 23 May 2022 Each enzyme has an active site, which is where the reaction takes place. Svenja Lohner, Scientific American, 10 Nov. 2016 See More

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'active site.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History

First Known Use

1957, in the meaning defined above

Time Traveler
The first known use of active site was in 1957

Dictionary Entries Near active site

Cite this Entry

“Active site.” Dictionary, Merriam-Webster, Accessed 24 Feb. 2024.

Medical Definition

active site

: a region especially of a biologically active protein (as an enzyme) where catalytic activity takes place and whose shape permits the binding only of a specific reactant molecule

More from Merriam-Webster on active site

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