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 combination supports the possibility that ancient nitrogenases more closely resembled this archaeal enzyme than the nitrogenases found in bacteria today.

From Science Daily ● Sep. 19, 2026

Genetically removing the enzyme that produces D-serine prevented or reduced several later cognitive problems.

From Science Daily ● Sep. 18, 2026

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

From BBC ● Sep. 17, 2026

Blocking the enzyme causes hydrogen peroxide to accumulate inside the mitochondria of tumor cells, eventually triggering cell death.

From Science Daily ● Sep. 17, 2026

It makes no difference which enzyme is affected.

From "Silent Spring" by Rachel Carson

Metallocofactors are metal-containing helper molecules that bind to enzymes and are essential for their activity.

From Science Daily ● Sep. 19, 2026

To survive that stressful environment, cancer cells increase production of antioxidant enzymes that help neutralize the damaging molecules.

From Science Daily ● Sep. 17, 2026

One of those enzymes is peroxiredoxin 3, or PRX3, which operates inside mitochondria, the structures that produce much of a cell's energy.

From Science Daily ● Sep. 17, 2026

Across both ancient and modern samples, populations living closer to tropical regions were more likely to carry genetic variants associated with higher expression of these enzymes.

From Science Daily ● Aug. 27, 2026

Leukocytes become more actively phagocytic, release lysosomal enzymes, turn sticky, and aggregate together in dense masses, occluding capillaries and shutting off the blood supply.

From "The Lives of a Cell" by Lewis Thomas

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