Meaning of enzyme: An enzyme is a specialized protein that speeds up a specific chemical reaction in the body without being consumed or permanently changed by it.

Definition of enzyme

An enzyme is a protein that speeds up a specific chemical reaction within the body without itself being permanently changed or used up in the process. Each enzyme is generally specific to one reaction or a narrow set of related reactions, recognizing a particular target molecule based on its shape and chemical structure.

Enzymes are involved in nearly every process that keeps the body functioning, including digesting food, copying and repairing DNA, and generating cellular energy. Many enzymes require the presence of a helper molecule, such as a vitamin derived cofactor, in order to function normally.

Because enzymes are so central to normal function, a missing, deficient, or malfunctioning enzyme can disrupt an entire chemical pathway, underlying a range of inherited metabolic conditions, and blood levels of certain enzymes are also measured clinically to help detect damage to specific organs, such as the liver or heart.

Used in a sentence

Blood testing showed elevated liver enzymes suggesting possible liver injury.

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Good to know

Elevated blood levels of certain enzymes are used to help detect damage to a specific organ, such as the liver or heart, since different tissues release characteristic enzymes when their cells are injured.

Word origin

Where “enzyme” comes from

Formed from Greek en-, meaning in, and zyme, meaning leaven, reflecting an early comparison to the fermenting action of yeast.

For learning, not diagnosis. This glossary provides general educational information and is not a substitute for advice from a qualified healthcare professional. If you may be experiencing a medical emergency, contact local emergency services.