Asked by: Kemo Matito
science chemistry

How is a substrate and its enzyme like a lock and its key?

Last Updated: 14th June, 2020

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The specific action of an enzyme with a single substrate can be explained using a Lock and Key analogy first postulated in 1894 by Emil Fischer. In this analogy, the lock is the enzyme and the key is the substrate. Only the correctly sized key (substrate) fits into the key hole (active site) of the lock (enzyme).

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Similarly one may ask, why is enzyme activity similar to a lock and key?

Explanation: As Vivi explained, enzyme specificity - that is, the enzyme's ability to bind only the correct substrates - comes from having a shape that is nearly perfect for one particular type of molecule. In that sense, the substrate fitting into the enzyme is like a key fitting into a lock.

Additionally, what is the lock and key principle? The lock and key hypothesis states that the substrate fits perfectly into the enzyme, like a lock and a key would. This is in contrast with the induced fit hypothesis, which states that both the substrate and the enzyme will deform a little to take on a shape that allows the enzyme to bind the substrate.

Furthermore, what is the lock and key model of an enzyme?

In 1894, German chemist Emil Fischer proposed the lock and key theory, which states that enzymes have a specific shape that directly correlates to the shape of the substrate. Basically, substrates fit into an enzyme the way a key fits into a lock.

Why does the lock and key analogy fit the linkage between an enzyme and its substrate?

The lock-and-key model portrays an enzyme as conformationally rigid and able to bond only to substrates that exactly fit the active site. The induced fit model portrays the enzyme structure as more flexible and is complementary to the substrate only after the substrate is bound.

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What factors affect enzyme activity?

Several factors affect the rate at which enzymatic reactions proceed - temperature, pH, enzyme concentration, substrate concentration, and the presence of any inhibitors or activators.

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How does pH affect enzyme activity?

pH: Each enzyme has an optimum pH range. Changing the pH outside of this range will slow enzyme activity. Extreme pH values can cause enzymes to denature. Enzyme concentration: Increasing enzyme concentration will speed up the reaction, as long as there is substrate available to bind to.

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How are enzymes produced?

Enzymes are made from amino acids, and they are proteins. When an enzyme is formed, it is made by stringing together between 100 and 1,000 amino acids in a very specific and unique order. The chain of amino acids then folds into a unique shape. Other types of enzymes can put atoms and molecules together.

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How are enzymes named?

Enzymes are named by adding the suffix -ase to the name of the substrate that they modify (i.e., urease and tyrosinase), or the type of reaction they catalyze (dehydrogenase, decarboxylase). Structurally, the vast majority of enzymes are proteins. Also RNA molecules have catalytic activity (ribozymes).

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Why is it called the lock and key model?

Enzymes only allow binding of molecules that can fit in their active site. As, these active sites (can be called locks) are very specific and only few molecules (can be called keys) can bind them, this model of enzyme working is called Lock and Key mechanism.

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What do you mean by enzymes?

Enzyme: Proteins that speeds up the rate of a chemical reaction in a living organism. An enzyme acts as catalyst for specific chemical reactions, converting a specific set of reactants (called substrates) into specific products. Without enzymes, life as we know it would not exist.

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How do coenzymes help enzymes?

Enzymes are proteins that speed up chemical reactions and often require cofactors to function. Non-protein organic cofactors are called coenzymes. Coenzymes assist enzymes in turning substrates into products. Specifically, coenzymes function by activating enzymes, or acting as carriers of electrons or molecular groups.

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What is the difference between induced fit and lock and key?

Lock and Key states that there is no change needed and that only a certain type will fit. However induced fit says the active site will change to help to substrate fit. In lock and key the active site has one single entry however in induced fit the active site is made of two components.

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What enzyme breaks down starch?

Carbohydrase enzymes break down starch into sugars. The saliva in your mouth contains amylase, which is another starch digesting enzyme. If you chew a piece of bread for long enough, the starch it contains is digested to sugar, and it begins to taste sweet.

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What are the two models of enzyme action?

The two models to explain the actions of enzymes with substrates are the Lock and Key model & Induced fit model. It suggests that it is the binding of the substrate to enzyme that causes the active site to change into a complementary shape and allow the enzyme-substrate complex to form.

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How does a catalyst work?

The production of most industrially important chemicals involves catalysis. A catalyst works by providing an alternative reaction pathway to the reaction product. The rate of the reaction is increased as this alternative route has a lower activation energy than the reaction route not mediated by the catalyst.

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How do enzymes work?

Enzymes are biological molecules (typically proteins) that significantly speed up the rate of virtually all of the chemical reactions that take place within cells. The molecules that an enzyme works with are called substrates. The substrates bind to a region on the enzyme called the active site.

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What causes an enzyme to denature?

Enzymes work consistently until they are dissolved, or become denatured. When enzymes denature, they are no longer active and cannot function. Extreme temperature and the wrong levels of pH -- a measure of a substance's acidity or alkalinity -- can cause enzymes to become denatured.

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What do Carbohydrase enzymes do?

Carbohydrases are the category of enzymes that break down carbohydrates and fibers (oligosaccharides) into simple sugars. One of the most popular carbohydrase enzymes is alpha-galactosidase. Proteases are enzymes that break down proteins into amino acids, and are also referred to as proteolytic enzymes.

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What is lock and key hypothesis in biology?

The lock and key hypothesis explains how the substrate (key) fits into the active site of the enzyme (lock). The substrate is complementary in shape to the active site and so only the correct substrate can fit; much like a key can only fit in one lock. Answered by William W. • Biology tutor.

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What does enzyme specificity mean?

The ability of enzyme to bind with specific substrate or catalyze a specific set of chemical reactions,is called "Enzyme Specificity". Some enzymes have an intrinsic property of binding with only one substrate and catalysing a single reaction. This property is called "Absolute Specificity".

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What happens to enzymes at low pH?

Describe and explain what happens to enzyme activity as the pH is decreased below the optimum pH. At extremely low pH values, this interference causes the protein to unfold, the shape of the active site is no longer complementary to the substrate molecule and the reaction can no longer be catalysed by the enzyme.

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Are enzymes proteins?

Enzymes are biological molecules (proteins) that act as catalysts and help complex reactions occur everywhere in life. Let's say you ate a piece of meat. Proteases would go to work and help break down the peptide bonds between the amino acids.

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What is induced fit theory?

allosteric control
…the basis of the so-called induced-fit theory, which states that the binding of a substrate or some other molecule to an enzyme causes a change in the shape of the enzyme so as to enhance or inhibit its activity.