enzyme

[en-zahym]

noun

Biochemistry.

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.

enzyme

/ ɛnˈzaɪmɪk, ˈɛnzaɪm, ˌɛnzaɪˈmætɪk, -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

enzyme

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.

enzyme

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.

Other Word Forms

• enzymatic adjective

Word History and Origins

Origin of enzyme¹

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

Word History and Origins

Origin of enzyme¹

C19: from Medieval Greek enzumos leavened, from Greek _en- ² + zumē leaven

Example Sentences

In autophagy, damaged or unnecessary proteins are enclosed in small membrane-bound vesicles and then broken down safely by enzymes, effectively recycling cellular components.

Read more on Science Daily

The researchers measured elevated levels of inflammation-promoting proteins and enzymes that indicate liver stress.

Read more on Science Daily

The protein ZAK -- a so-called kinase, that is, an enzyme which activates other molecules by transferring a phosphate group to them -- plays a central role in controlling this stress response.

Read more on Science Daily

Nitrogen-fixing bacteria generate an enzyme called nitrogenase, sometimes referred to as the "fixer" because it carries out nitrogen fixation.

Read more on Science Daily

Due to a faulty gene, before the treatment Oliver was unable to produce an enzyme crucial for keeping cells healthy.

Read more on BBC

Related Words

• impetus 
• incentive 
• motivation 
• stimulant