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Coenzyme Definition

Enzymes are proteinaceous molecules that help in catalyzing the biochemical reactions in our body. thanks to this property, they're also referred to as biocatalysts. As they're proteinaceous in nature, they also possess secondary and tertiary structures. When the enzymes are present in their tertiary structure, their protein chains get folded upon themselves and thanks to this many crevices are formed that are termed as active. The coenzyme may be a non-protein molecule that's organic in nature. Another name of the coenzyme is co-factors. We'll learn more about ubiquinone, coenzyme q10 use, ubiquinol, and the functions of enzymes.

Enzyme Functions

The coenzyme, as we studied above are the factors that are liable for catalyzing the enzyme reactions. Other factors aside from co-enzymes help in enzyme catalysis.

Three factors are liable for affecting the mechanism of enzyme catalysis:

  • Temperature: Enzyme catalysis works during a narrow range of temperature. Optimum temperature is the temperature at which the enzymes show the very best catalytic activity. Coldness makes the enzymes inactive whereas heat denatures the structure of enzymes.

  • Hydrogen Ion Concentration: As there's an optimum temperature required for the enzyme to function, there's also an optimum pH concentration. Sometimes a fall in pH activity declines the activity of enzymes. 

  • Substrate Concentration: Substrates act on enzymes that are changed to products, a rise within the concentration of substrate leads to increasing the speed of enzymes.

The various functions of enzymes are:

  • Enzymes are important within the process of transferring signals from one cell to a different cell. during this process, a chemical or physical signal is transmitted through a cell which is governed by a series of molecular events then a cellular response takes place.

  • In the process of digestion, enzymes help break down large molecules into smaller molecules because many nutritional contents like sugars, fat, and protein are present in large molecules and can't be haunted by the physical body therefore they're needed to be weakened.

  • Enzymes are widely utilized in the sector of biotechnology as molecular scissors to chop DNA fragments or as polymerases to feature DNA/RNA fragments.

  • Enzymes also are liable for the generation of movement within the physical body with the assistance of myosin which hydrolyzes ATP to get energy.


As we read above that the enzymes are composed of several polypeptide chains. But there are some enzymes that are ready to exhibit catalytic activity only they're present in association with certain other substances. These substances are non-proteinaceous in nature. These substances are referred to as coenzymes or cofactors. The portion of the protein that's present in them is understood as apoenzyme. There are three sorts of cofactors:

  • Prosthetic Group: These groups are organic in nature. They're tightly sure to the apoenzyme. This will be understood by one simple example of a haem group. Within the peroxidase enzyme, haem is that the prosthetic group. It helps in catalysing the breakdown of hydrogen. The haem may be a prosthetic group that's present on the site of the enzyme.

  • Coenzymes: The association of those groups last for less than a brief period of your time. When the method of catalysis is close to happening then at that point only the association occurs. Vitamins are essential components of the many coenzymes. For instance, Niacin is present as a coenzyme for NADP.

  • Metal Ions: The metal ions are required by many enzymes. They form coordination bonds with the enzymes. For carboxypeptidase, zinc may be a cofactor. Sometimes, if the coenzyme is far away from the enzyme, then the catalytic activity of the enzyme is lost. So we can state that the coenzymes have an important role within the catalytic activity of the enzyme.

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Ubiquinol is additionally referred to as coenzyme q. Another name for it is CoQ10. It plays a crucial role in the metabolism of the body. It also acts as an anti-oxidant and also helps in protecting the cells from damage. The coenzyme q10 use in some ways. They are:

  • It is often used to treat heart failures and other heart diseases.

  • They can be used to treat muscle pains.

  • They can be used to treat liver infections.

  • They can hamper the progression of Alzheimer's disease.

  • They can even be used to treat migraine disease.

These are a number of the cases where coenzymeq10 use.

Coenzyme A Vitamin

It is also referred to as Vitamin B5 or pantothenic acid. It is present in some foods and is extremely essential to the body. It is available as a dietary supplement. For the synthesis of coenzyme A, B-complex vitamin is extremely essential.

Interesting Facts about Enzymes

The enzymes play a really crucial role in our daily lives. They assist in lowering the energy of activation and speed up the chemical reactions. A number of the interesting features of enzymes are:

  • Enzymes are very temperature-specific. They get damaged at high temperatures which are above 40 degrees celsius.

  • Enzymes play a crucial role in the digestion of food in our body. They are found within the saliva, pancreas, stomach, and little intestines.

  • Enzymes are even utilized in industries like food processing, paper industries, and detergents.

  • Enzymes also are pH specific.

  • They are also concentration-specific. 

  • Enzymes aren't spent within the reaction and may be used again and again.

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FAQs on Coenzyme

1. Explain Lock and Key Hypothesis.

Answer: This hypothesis was proposed by Emil Fischer in 1894. This hypothesis helps us to know the mechanism of action of enzymes. Consistent with this hypothesis, the enzyme and substrate molecules exhibit various geometrical shapes and these shapes are very specific. Even as the lock and key model, this hypothesis states that the active sites of enzymes act as a lock that has specific molecules like -COOH, -SH. These enzyme molecules can only be opened with the assistance of specific substrate complexes. This hypothesis explains the specificity of enzymes and also the mode of action of enzymes. The substrate comes in touch with the site of the enzyme complex then forms an enzyme-substrate complex. When this complex is made, then it undergoes chemical changes, then eventually a product is made. When this product is made, if it does not fit into the site then it escapes out into the encompassing. In this way, the site is out there again for fresh substrates. By this hypothesis, it is often concluded that a bit of enzyme can influence large substrate molecules. It also explains how the enzymes aren't utilized in the reaction and may be used again and again. Moreover, it helps us to know the mechanism of competitive inhibition.

2. Explain the Induced Fit Model Hypothesis.

Answer: Koshland proposed this hypothesis within the year 1960. This hypothesis is quite different from the previous hypothesis. It states that the site of the enzyme is flexible in shape and may change its shape consistent with the character of the substrate, which suggests that it can form its site complementary to the substrate. It is easy to know in a way that how a hand induces a change within the glove, that's an equivalent way a lively site induces a change within the chemical substrate. The substrate gets into the site of the enzyme. Consistent with this, the structure of the site of an enzyme is flexible. There are two sorts of groups that are present within the site of the enzyme. One may be a buttressing group and therefore the other may be a catalytic group. The buttressing group helps in supporting the substrate whereas the catalytic group helps to elucidate the mechanism of enzyme catalyzes. When the buttressing group comes in touch with the substrate, changes happen within the site and these changes help to bring the catalytic group opposite to the substrate bonds that are needed to be broken.