Catalyst
A substance that speeds up a chemical reaction but is not consumed or altered in the process. Catalysts are of immense importance in chemistry and biology. All enzymes are catalysts that expedite the biochemical reactions necessary for life. The enzymes in saliva, for example, accelerate the conversion of starch to glucose, doing in minutes what would otherwise take weeks. The word “catalyst” was introduced into science by the great Swedish chemist Jons Jakob Berzelius (1779-1848) who also determined the atomic and molecular weights of thousands of substances, discovered several elements including selenium, first isolated silicon and titanium, and created the present system of writing chemical symbols and reactions.
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A substance that accelerates a chemical reaction but is not consumed or changed permanently thereby. SYN: catalyzer.
- inorganic c. a c. such as a finely divided metal (Pt, Rh), carbon, etc.
- negative c. a c. that retards a reaction.
- organic c. 1. SYN: enzyme, ribozyme. 2. a c. that is an organic molecule.
- Raney c. SYN: Raney Nickel.

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cat·a·lyst 'kat-əl-əst n a substance (as an enzyme) that enables a chemical reaction to proceed under different conditions (as at a lower temperature) than otherwise possible

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n.
a substance that alters the rate of a chemical reaction but is itself unchanged at the end of the reaction. The catalysts of biochemical reactions are the enzyme.

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cat·a·lyst (katґə-list) any substance that brings about catalysis; called also accelerant.

Medical dictionary. 2011.

Look at other dictionaries:

  • catalyst — UK US /ˈkætəlɪst/ noun [C] ► someone or something that causes a big change: the catalyst behind sth »The catalyst behind this welcome trend has been the mighty Bill Gates. catalyst for sth »An outside leader is often needed to serve as a catalyst …   Financial and business terms

  • catalyst — n. 1. (Chem.) a substance that initiates or accelerates a chemical reaction without itself being affected; as, thousands of enzymes serve in concert as calaysts to produce the sequence of reactions we call life ; the industrial production of… …   The Collaborative International Dictionary of English

  • Catalyst — Saltar a navegación, búsqueda Catalyst puede referirse a: Catalyst (controladores) Catalyst (framework) Catalyst (álbum) de New Found Glory Obtenido de Catalyst Categoría: Wikipedia:Desambiguación …   Wikipedia Español

  • Catalyst — (englisch für Katalysator) steht für: ein Gerätetreiber Paket für Radeon Grafikkarten, siehe AMD Catalyst ein in Perl geschriebenes MVC Web Framework, siehe Catalyst Web Framework eine Produktbezeichnung für eine Serie von Ethernet Switches der… …   Deutsch Wikipedia

  • Catalyst — Catalyst. См. Катализатор. (Источник: «Металлы и сплавы. Справочник.» Под редакцией Ю.П. Солнцева; НПО Профессионал , НПО Мир и семья ; Санкт Петербург, 2003 г.) …   Словарь металлургических терминов

  • catalyst — I noun abettor, activator, active element, active partisan, active reformer, actuator, agacerie, agent provocateur, agitator, animator, catalytic agent, cause, encouragement, encourager, excitant, exciter, ferment, force, goad, impeller, impetus …   Law dictionary

  • catalyst — (n.) 1902, formed in English (on analogy of analyst) from CATALYSIS (Cf. catalysis) …   Etymology dictionary

  • catalyst — [n] something which incites activity adjuvant, agitator, enzyme, goad, impetus, impulse, incendiary, incentive, incitation, incitement, motivation, radical stimulus, reactant, reactionary, spark plug*, spur, stimulant, synergist, wave maker*;… …   New thesaurus

  • catalyst — ► NOUN 1) a substance that increases the rate of a chemical reaction without itself undergoing any permanent chemical change. 2) a person or thing that precipitates an event …   English terms dictionary

  • catalyst — [kat′ə list΄] n. 1. any substance serving as the agent in catalysis 2. a person or thing acting as the stimulus in bringing about or hastening a result catalytic [kat′əlit′ik] adj. catalytically adv …   English World dictionary

  • Catalyst — Это статья о веб фреймворке. О наборе системного ПО AMD/ATI см. ATI Catalyst. Catalyst Тип Программный каркас для создания веб приложений Разработчики Jonathan Rockway, David Kamholz, Brian Cassidy, Yuval Kogman, Matt S. Trout, Jesse Sheidlower,… …   Википедия

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