enzyme

American  

[en-zahym] / ˈɛn zaɪm /

noun

Biochemistry.

• enzymes
  plural

1. any of various proteins, as pepsin, originating from living cells and capable of producing certain chemical changes in organic substances by catalytic action, as in digestion.

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enzyme British  

/ ˈɛnzaɪm, -zɪ-, -ˈzɪm- /

noun

1. any of a group of complex proteins or conjugated proteins that are produced by living cells and act as catalysts in specific biochemical reactions

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enzyme Scientific  

/ ĕn′zīm /

1. Any of numerous proteins produced in living cells that accelerate or catalyze the metabolic processes of an organism. Enzymes are usually very selective in the molecules that they act upon, called substrates, often reacting with only a single substrate. The substrate binds to the enzyme at a location called the active site just before the reaction catalyzed by the enzyme takes place. Enzymes can speed up chemical reactions by up to a millionfold, but only function within a narrow temperature and pH range, outside of which they can lose their structure and become denatured. Enzymes are involved in such processes as the breaking down of the large protein, starch, and fat molecules in food into smaller molecules during digestion, the joining together of nucleotides into strands of DNA, and the addition of a phosphate group to ADP to form ATP. The names of enzymes usually end in the suffix –ase.

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enzyme Cultural  

1. A protein molecule that helps other organic molecules (see also organic molecule) enter into chemical reactions with one another but is itself unaffected by these reactions. In other words, enzymes act as catalysts for organic biochemical reactions.

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Other Word Forms

Derived Forms

• enzymatic
  adjective

Inflected Forms

Nouns

• enzymes
  plural

Etymology

Origin of enzyme

First recorded in 1880–85; from Medieval Greek énzymos “leavened,” from Greek en- en- ² + zȳ́m(ē) “leaven” + -os, adjective suffix

Explanation

An important element in human chemistry, an enzyme is a protein manufactured by a cell, and is a catalyst in various biological functions. For example, enzymes help break down larger molecules of starch, fat, and protein during digestion. The word enzyme was coined by a German physiologist in the late 1800s to name a digestive process that scientists had been observing. The word was later given to the actual agents discovered to spark the reactions, taken from the Greek énzymos, which meant "leavened." (Leavening makes bread rise.) Remember that the word enzyme is spelled with a y and not an i, which makes sense, since when scientists observe chemical processes, they often ask "why?"

Example Sentences

See Examples For:

enzyme enzymes

That's also the case during pregnancy, when hormonal changes suppress the liver enzyme that breaks down caffeine.

From BBC ● Sep. 17, 2026

All this time it's also being broken down – or metabolised – by an enzyme in the liver and then flushed out in our urine.

From BBC ● Sep. 17, 2026

Under normal conditions, sEH breaks down epoxy-oxylipins, so blocking the enzyme allows more of these protective molecules to remain in the body.

From Science Daily ● Sep. 13, 2026

To test whether SETD7 itself could produce these changes, the scientists artificially increased the enzyme in young mice that had not experienced early-life stress.

From Science Daily ● Aug. 26, 2026

In the same way, if we destroy an enzyme that functions at any point in the cycle, oxidation ceases.

From "Silent Spring" by Rachel Carson

Novonesis—which develops enzymes, probiotics and other biological products—on Thursday posted organic sales growth of 9% on year for the second quarter, ahead of consensus estimates of 7.4%.

From The Wall Street Journal ● Aug. 20, 2026

Restriction enzymes, however, can only recognize and cut certain DNA sequences.

From Science Daily ● Aug. 19, 2026

Standard methods for assembling long DNA molecules typically use restriction enzymes to make cuts and T4 DNA ligase to connect the resulting fragments.

From Science Daily ● Aug. 19, 2026

In a study published in Nature Ecology & Evolution, researchers found that a wide range of animals, including marine worms, starfish, earthworms, and other terrestrial species, possess enzymes that can degrade microbial PHAs.

From Science Daily ● Aug. 17, 2026

The detoxification is accomplished by one of the enzymes of the liver.

From "Silent Spring" by Rachel Carson

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