enzyme

n. a protein that acts as a biological catalyst, accelerating the rate of a biochemical reaction without itself becoming permanently altered. Many enzymes require other organic molecules (coenzymes) or inorganic ions (cofactors) to function normally. Most enzymes are named according to the type of reaction they catalyze; for example, glucosidases convert glucosides to glucose; acetylcholinesterase (see cholinesterase) splits and inactivates molecules of the neurotransmitter acetylcholine.

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Psychology term of the day

November 19th 2024

Betz cell

a type of large pyramidal cell found in the fifth layer of the cerebral cortex (see cortical layers), mainly in motor cortex. Betz cells are associated with muscle movement and have a low threshold of stimulation. [Vladimir A. Betz (1834–1894), Russian anatomist]