Name: how enzymes adjust to their substrates
Uploaded: 2019-03-11T09:21:10.000Z
Duration: 1 min 13 s
Channel: JoVE

Enzimas, que geralmente são proteínas, funcionam ligando-se a um substrato, uma molécula sobre a qual elas atuam e têm especificidade para. O que significa que elas só podem se ligar a certos substratos. Esta propriedade é determinada principalmente pela forma e características químicas de seu sítio ativo, a região da enzima que se liga ao substrato.Consistente com o ajuste induzido do modelo de atividade enzimática, esta ligação muda a confirmação, da forma, de ambos enzima e o substrato. Isto aproxima o substrato do estado de transição de energia mais elevado, necessário, para que a reação ocorra. Por exemplo, enfraquecendo seus laços para que possa reagir mais prontamente.Após o produto do reação ser produzido, a enzima é liberada e pode ser usada para catalisar as reações mais uma vez.

modelo de encaixe induzido

Induced-fit Model

A maioria das reações químicas nas células requer enzimas—catalisadores biológicos que aceleram a reação sem serem usados ou alterados permanentemente. Eles trabalham reduzindo a energia de ativação necessária para que os reagentes sejam convertidos nos produtos. As enzimas, que geralmente são proteínas, funcionam ligando-se a um substrato—uma molécula reagente sobre a qual elas agem.
 
 <h4>Especificidade</h4>
 
 As enzimas exibem especificidade de substrato, o que significa que elas só se podem ligar a certos substratos. Isso é determinado principalmente pela forma e características químicas do seu local ativo—a região da enzima que se liga ao substrato.
 
 De acordo com o modelo de encaixe induzido de atividade enzimática, essa ligação altera a conformação—ou forma—tanto da enzima como do substrato. Isso aproxima o substrato do estado de transição energética mais elevado necessário para que a reação ocorra, por exemplo, enfraquecendo as suas ligações para que possa reagir mais facilmente. As enzimas também podem acelerar uma reação criando condições dentro do local ativo que são mais propícias para que a reação prossiga do que o ambiente celular circundante.
 
 Uma vez formados os produtos da reação, eles são libertados do local ativo e a enzima pode ser novamente usada para catalisar reações.

Modelo de Encaixe Induzido

A maioria das reações químicas nas células requer enzimas - catalisadores biológicos que aceleram a reação sem serem consumidos ou alterados permanentemente. Eles...

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how enzymes adjust to their substrates

Enzymes speed up many chemical reactions in cells. They are biological catalysts, so they increase reaction speed without being consumed or permanently changed. They do this by lowering the activation energy needed to turn reactants into products.

Enzymes are proteins that usually work by binding to a substrate, which is the reactant molecule they act on. They show substrate specificity, meaning they bind only certain substrates. This specificity depends mainly on the shape and chemical features of the enzyme’s active site, the region that binds the substrate.

The induced-fit model explains what happens after the substrate binds. The binding changes the enzyme’s shape, or conformation. This change helps bring the substrate closer to the higher-energy transition state needed for the reaction, such as by weakening bonds so the substrate can react more easily.

Enzymes can also make the active site a better place for the reaction than the surrounding cell environment. After the products form, they leave the active site. The enzyme can then catalyze the reaction again.

How Enzymes Adjust to Their Substrates

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key terms and concepts

Learn how enzyme active sites change shape in the induced-fit model, helping substrates reach the transition state and reactions happen faster.

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How Enzymes Adjust to Their Substrates

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