This video will help you to further understand the lock-and-key hypothesis.
Tuesday, February 8, 2011
HOW DO ENZYMES WORK?
Enzymes work by something called the lock-and-key hypothesis.
When the chemicals that are involved in a reaction get near an enzyme molecule, they ‘fit’ into part of the enzyme called the active site, just like how a key fits into a lock!
That is why enzymes are very specific! The active site has to perfectly fit the substrate in order for reaction to take place.
The chemicals that are supposed to be fitted are called the substrates.
When the substrate fits into the active site, it forms something called the enzyme-substrate complex.
After they fit, the substrates will break off to become the product of the enzyme reaction, but the enzyme remains unaffected.
This allows it to catalyze another reaction again, and again, and again, and again until it can’t catalyze anymore!
When the chemicals that are involved in a reaction get near an enzyme molecule, they ‘fit’ into part of the enzyme called the active site, just like how a key fits into a lock!
That is why enzymes are very specific! The active site has to perfectly fit the substrate in order for reaction to take place.
The chemicals that are supposed to be fitted are called the substrates.
When the substrate fits into the active site, it forms something called the enzyme-substrate complex.
After they fit, the substrates will break off to become the product of the enzyme reaction, but the enzyme remains unaffected.
This allows it to catalyze another reaction again, and again, and again, and again until it can’t catalyze anymore!
PROPERTIES OF ENZYMES
1. Enzymes are proteins.
-This is one of the reasons why we need an adequate amount of protein in our body.
2. Enzymes are all biological catalysts.
-They remain unaffected after a reaction and it can be used over and over again.
3. A small amount of enzyme can catalyze a large amount of chemicals.
4. Enzymes are affected by temperature, acidity, and alkalinity.
-Enzymes can be denatured, or in layman terms, be “killed” by high temperatures. They are inactive when the temperature is too low. They can only work in optimum temperature, acidity and alkalinity.
5. Enzymes are extremely specific in nature.
-One type of enzyme works only on one type of chemical.
-This is one of the reasons why we need an adequate amount of protein in our body.
2. Enzymes are all biological catalysts.
-They remain unaffected after a reaction and it can be used over and over again.
3. A small amount of enzyme can catalyze a large amount of chemicals.
4. Enzymes are affected by temperature, acidity, and alkalinity.
-Enzymes can be denatured, or in layman terms, be “killed” by high temperatures. They are inactive when the temperature is too low. They can only work in optimum temperature, acidity and alkalinity.
5. Enzymes are extremely specific in nature.
-One type of enzyme works only on one type of chemical.
SPECIFICITY OF ENZYMES
One of the properties of enzymes that makes them so important as diagnostic and research tools, is the specificity they exhibit relative to the reactions they catalyze. Each enzyme will only work on one type of substrate/substance.
This means that they control only one reaction; for example, maltase only acts on maltose, and sucrase on sucrose!
In general, there are four distinct types of specificity:
~ ABSOLUTE SPECIFICITY
- the enzyme will only catalyze one reaction.
~ GROUP SPECIFICITY
- the enzyme will only act on molecules that have specific functional groups.
~ LINKAGE SPECIFICITY
- the enzyme will act on a particular type of chemical bond regardless of the rest of the molecular structure.
~ STEREOCHEMICAL SPECIFICITY
- the enzyme will act on a particular steric or optical isomer.
The picture above is able to help us relate to the fact that enzymes are very specific.
This above video is about enzyme action.
This means that they control only one reaction; for example, maltase only acts on maltose, and sucrase on sucrose!
In general, there are four distinct types of specificity:
~ ABSOLUTE SPECIFICITY
- the enzyme will only catalyze one reaction.
~ GROUP SPECIFICITY
- the enzyme will only act on molecules that have specific functional groups.
~ LINKAGE SPECIFICITY
- the enzyme will act on a particular type of chemical bond regardless of the rest of the molecular structure.
~ STEREOCHEMICAL SPECIFICITY
- the enzyme will act on a particular steric or optical isomer.
The picture above is able to help us relate to the fact that enzymes are very specific.
This above video is about enzyme action.
SO WHAT EXACTLY ARE ENZYMES?
They are biocatalysts (biological catalysts) which speed up the rate of chemical reaction without itself being affected.
Enzymes consist of various types of proteins that work to drive the chemical reaction required for a specific action or nutrient.
The chemicals that are transformed with the help of enzymes are called substrates. In the absence of enzymes, these chemicals are called reactants.
To illustrate the speed and efficiency of enzymes, substrates can be transformed to usable products at the rate of ten times per second.
Considering that there are an estimated 75,000 different enzymes in the human body, these chemical reactions are performed at an amazing rate.
On the other hand, in the absence of enzymes, reactants may take hundreds of years to convert into a usable product, if they are able to do so at all.
This is why enzymes are crucial in the sustenance of life on earth.
Enzymes are usually very specific as to which reactions they catalyze and the substrates that are involved in these reactions.
Complementary shape, charge and hydrophilic/hydrophobic characteristics of enzymes and substrates are responsible for this specificity.
sources: http://www.wisegeek.com/what-are-enzymes.htm & http://en.wikipedia.org/wiki/Enzyme
Enzymes consist of various types of proteins that work to drive the chemical reaction required for a specific action or nutrient.
The chemicals that are transformed with the help of enzymes are called substrates. In the absence of enzymes, these chemicals are called reactants.
To illustrate the speed and efficiency of enzymes, substrates can be transformed to usable products at the rate of ten times per second.
Considering that there are an estimated 75,000 different enzymes in the human body, these chemical reactions are performed at an amazing rate.
On the other hand, in the absence of enzymes, reactants may take hundreds of years to convert into a usable product, if they are able to do so at all.
This is why enzymes are crucial in the sustenance of life on earth.
Enzymes are usually very specific as to which reactions they catalyze and the substrates that are involved in these reactions.
Complementary shape, charge and hydrophilic/hydrophobic characteristics of enzymes and substrates are responsible for this specificity.
sources: http://www.wisegeek.com/what-are-enzymes.htm & http://en.wikipedia.org/wiki/Enzyme
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