Changes

==Origin==

==Origin==

German ''Enzym'', from Middle Greek ''enzymos'' leavened, from [[Greek]] ''en''- + ''zymē'' [[leaven]]

German ''Enzym'', from Middle Greek ''enzymos'' leavened, from [[Greek]] ''en''- + ''zymē'' [[leaven]]

*[http://en.wikipedia.org/wiki/19th_century 1881]

*[https://en.wikipedia.org/wiki/19th_century 1881]

In 1877, German physiologist [http://en.wikipedia.org/wiki/Wilhelm_K%C3%BChne Wilhelm Kühne] (1837–1900) first used the term ''enzyme'', which comes from Greek ενζυμον, "in [[leaven]]", to describe this [[process]]. The word enzyme was used later to refer to nonliving substances such as [http://en.wikipedia.org/wiki/Pepsin pepsin], and the word ferment was used to refer to chemical activity produced by living [[organisms]].

In 1877, German physiologist [https://en.wikipedia.org/wiki/Wilhelm_K%C3%BChne Wilhelm Kühne] (1837–1900) first used the term ''enzyme'', which comes from Greek ενζυμον, "in [[leaven]]", to describe this [[process]]. The word enzyme was used later to refer to nonliving substances such as [https://en.wikipedia.org/wiki/Pepsin pepsin], and the word ferment was used to refer to chemical activity produced by living [[organisms]].

==Definition==

==Definition==

*1:  any of numerous [[complex]] [http://en.wikipedia.org/wiki/Protein proteins] that are produced by living [[cells]] and [[catalyze]] specific [[biochemical]] [[reactions]] at body temperatures.

*1:  any of numerous [[complex]] [https://en.wikipedia.org/wiki/Protein proteins] that are produced by living [[cells]] and [[catalyze]] specific [[biochemical]] [[reactions]] at body temperatures.

==Description==

==Description==

'''Enzymes''' /ˈɛnzaɪmz/ are large [[biological]] [[molecules]] responsible for the thousands of [http://en.wikipedia.org/wiki/Metabolism metabolic processes] that sustain life. They are highly selective catalysts, greatly [[accelerating]] both the rate and specificity of metabolic reactions, from the digestion of food to the synthesis of [[DNA]]. Most enzymes are proteins, although some [http://en.wikipedia.org/wiki/Ribozyme catalytic RNA molecules] have been identified. Enzymes adopt a specific[http://en.wikipedia.org/wiki/Protein_structure three-dimensional structure], and may employ organic (e.g. biotin) and inorganic (e.g. magnesium ion) cofactors to assist in catalysis.

'''Enzymes''' /ˈɛnzaɪmz/ are large [[biological]] [[molecules]] responsible for the thousands of [https://en.wikipedia.org/wiki/Metabolism metabolic processes] that sustain life. They are highly selective catalysts, greatly [[accelerating]] both the rate and specificity of metabolic reactions, from the digestion of food to the synthesis of [[DNA]]. Most enzymes are proteins, although some [https://en.wikipedia.org/wiki/Ribozyme catalytic RNA molecules] have been identified. Enzymes adopt a specific[https://en.wikipedia.org/wiki/Protein_structure three-dimensional structure], and may employ organic (e.g. biotin) and inorganic (e.g. magnesium ion) cofactors to assist in catalysis.

In enzymatic reactions, the molecules at the beginning of the [[process]], called [http://en.wikipedia.org/wiki/Substrate_(biochemistry) substrates], are converted into different molecules, called products. Almost all chemical reactions in a biological cell need enzymes in order to occur at rates sufficient for [[life]]. Since enzymes are selective for their substrates and speed up only a few reactions from among many possibilities, the set of enzymes made in a cell determines which [http://en.wikipedia.org/wiki/Metabolic_pathway metabolic pathways] occur in that cell.

In enzymatic reactions, the molecules at the beginning of the [[process]], called [https://en.wikipedia.org/wiki/Substrate_(biochemistry) substrates], are converted into different molecules, called products. Almost all chemical reactions in a biological cell need enzymes in order to occur at rates sufficient for [[life]]. Since enzymes are selective for their substrates and speed up only a few reactions from among many possibilities, the set of enzymes made in a cell determines which [https://en.wikipedia.org/wiki/Metabolic_pathway metabolic pathways] occur in that cell.

Like all catalysts, enzymes work by lowering the [http://en.wikipedia.org/wiki/Activation_energy activation energy] (Ea‡) for a reaction, thus dramatically increasing the [http://en.wikipedia.org/wiki/Reaction_rate rate of the reaction]. As a result, products are formed faster and reactions reach their [http://en.wikipedia.org/wiki/Chemical_equilibrium equilibrium] state more rapidly. Most enzyme reaction rates are millions of times faster than those of comparable un-catalyzed reactions. As with all catalysts, enzymes are not consumed by the reactions they catalyze, nor do they alter the equilibrium of these reactions. However, enzymes do differ from most other catalysts in that they are highly specific for their substrates. Enzymes are known to catalyze about 4,000 biochemical reactions.[3] A few RNA molecules called [http://en.wikipedia.org/wiki/Ribozyme ribozymes] also catalyze reactions, with an important example being some parts of the [http://en.wikipedia.org/wiki/Ribosome ribosome]. Synthetic molecules called artificial enzymes also display enzyme-like catalysis.

Like all catalysts, enzymes work by lowering the [https://en.wikipedia.org/wiki/Activation_energy activation energy] (Ea‡) for a reaction, thus dramatically increasing the [https://en.wikipedia.org/wiki/Reaction_rate rate of the reaction]. As a result, products are formed faster and reactions reach their [https://en.wikipedia.org/wiki/Chemical_equilibrium equilibrium] state more rapidly. Most enzyme reaction rates are millions of times faster than those of comparable un-catalyzed reactions. As with all catalysts, enzymes are not consumed by the reactions they catalyze, nor do they alter the equilibrium of these reactions. However, enzymes do differ from most other catalysts in that they are highly specific for their substrates. Enzymes are known to catalyze about 4,000 biochemical reactions.[3] A few RNA molecules called [https://en.wikipedia.org/wiki/Ribozyme ribozymes] also catalyze reactions, with an important example being some parts of the [https://en.wikipedia.org/wiki/Ribosome ribosome]. Synthetic molecules called artificial enzymes also display enzyme-like catalysis.

Enzyme activity can be affected by other molecules. [http://en.wikipedia.org/wiki/Enzyme_inhibitor Inhibitors] are molecules that decrease enzyme activity; [http://en.wikipedia.org/wiki/Enzyme_activator activators] are molecules that increase activity. Many [[drugs]] and [[poisons]] are enzyme inhibitors. Activity is also affected by [[temperature]], [[pressure]], chemical environment (e.g., pH), and the concentration of substrate. Some enzymes are used commercially, for example, in the synthesis of antibiotics. In addition, some household products use enzymes to speed up biochemical reactions (e.g., enzymes in biological washing powders break down protein or [http://en.wikipedia.org/wiki/Fat fat] stains on clothes; enzymes in meat tenderizers break down proteins into smaller molecules, making the meat easier to chew).[http://en.wikipedia.org/wiki/Enzyme]

Enzyme activity can be affected by other molecules. [https://en.wikipedia.org/wiki/Enzyme_inhibitor Inhibitors] are molecules that decrease enzyme activity; [https://en.wikipedia.org/wiki/Enzyme_activator activators] are molecules that increase activity. Many [[drugs]] and [[poisons]] are enzyme inhibitors. Activity is also affected by [[temperature]], [[pressure]], chemical environment (e.g., pH), and the concentration of substrate. Some enzymes are used commercially, for example, in the synthesis of antibiotics. In addition, some household products use enzymes to speed up biochemical reactions (e.g., enzymes in biological washing powders break down protein or [https://en.wikipedia.org/wiki/Fat fat] stains on clothes; enzymes in meat tenderizers break down proteins into smaller molecules, making the meat easier to chew).[https://en.wikipedia.org/wiki/Enzyme]

[[Category: Biology]]

[[Category: Biology]]

[[Category: Chemistry]]

[[Category: Chemistry]]