What does enzyme mean?
An enzyme is a protein produced by living organisms that functions as a catalyst, meaning it dramatically accelerates a specific chemical reaction without being used up in the process. Every living cell depends on hundreds of different enzymes to carry out the reactions necessary for life — from breaking down food during digestion to copying DNA when cells divide. Each enzyme is highly selective, typically acting on only one particular substance, known as its substrate. The word appears most often in scientific and medical contexts, but has entered everyday language through discussions of nutrition, digestion, laundry detergents, and cosmetics, where enzymes are valued for their ability to break down stains or aid skin renewal. Because enzymes are so efficient — often speeding up reactions millions of times faster than they would occur otherwise — the word also carries connotations of natural efficiency and biological precision, making it a useful and evocative term well beyond the laboratory.
nounA protein produced by living cells that acts as a biological catalyst, speeding up specific chemical reactions in the body without itself being consumed or permanently altered.
- A protein produced by living cells that catalyzes a specific biochemical reaction, such as digestion or metabolism.
"The enzyme amylase begins breaking down starch into sugars the moment food enters the mouth."
"The enzyme lactase breaks down lactose in milk for people who are not lactose intolerant."
"Forensic scientists used an enzyme called DNA polymerase to amplify traces of genetic material at the crime scene."
Standard English plural. Often used generically when discussing classes or groups of enzymes.
"Enzymes in the stomach work best in acidic conditions."
Without enzymes, digestion of a single meal would take roughly 50 years — these tiny proteins speed up reactions by up to a million times.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of enzyme
The word enzyme was coined in 1878 by the German physiologist Wilhelm Kühne from Greek roots: en- meaning 'in' or 'within', and zymē meaning 'leaven' or 'yeast'. It originally distinguished enzymes produced within living cells from the non-living ferments already known to cause fermentation. The Greek zymē root also gives us related words such as zymology, the study of fermentation, and appears in the names of specific enzymes like lysozyme.
Related word forms
How enzyme is actually used
Enzyme is a technical term common in biochemistry, biology, medicine, and increasingly in everyday contexts like nutrition labels, skincare products, and household cleaning products. It is neutral in register. Individual enzymes are usually referred to by their proper name (e.g. amylase, pepsin) rather than simply 'enzyme' in scientific writing.
Easily confused with enzyme
An enzyme is a biological catalyst that speeds up chemical reactions, while a hormone is a chemical messenger that travels through the bloodstream to regulate bodily processes.
An enzyme is a large protein molecule that directly catalyzes reactions; a vitamin is a small organic compound, often required as a cofactor, that the body cannot synthesize and must obtain from the diet.