7 Characteristics Of enzyme

There are thousands of enzymes in our body, in the plants we care for, in our pets and in many other organisms, such as bacteria or viruses. Due to this immense amount, the scientific community decided to make only a few small changes to them, compared to the substrates or the reactions with which they interact, to name them. Thus, enzymes are named according to the name of the reaction or compound with which they react, but with the suffix -asa.

For example, the enzyme dehydrogenase participates by removing or adding hydrogen atoms, and oxidase is responsible for catalyzing oxidation reactions. It should be noted that, although most enzymes end with the suffix asa, there are also others that do so with the suffix -ine, for example pepsin or papain.

If you are interested in learning more about what enzymes are and their types , we invite you to continue reading this article where you will learn about it and other information about enzymes.

What are enzymes

Enzymes are organic molecules , specifically proteins, that serve as catalysts for the different chemical reactions that occur in biological processes. When we say that enzymes are catalysts, we are referring to the fact that they are capable of accelerating the speed of chemical reactions , in such a way that they are carried out correctly and 100%.

Enzymes will always work on substances called substrates. So, in an enzymatic catalysis the following occurs:

  • The enzyme (E) finds its specific substrate (S) and binds to it through its active site.
  • A transient complex is formed by the union of the enzyme and the substrate, which is called the enzyme-substrate complex (ES). During this union the catalytic action of the enzyme takes place.
  • After the reactions are carried out, the ES complex dissociates into the enzyme and products.
  • In this article you can learn more about Proteins: what they are, functions and classification .

Characteristics Of enzyme

Enzymes are proteins that play a crucial role in catalyzing chemical reactions in living organisms. Here are some key characteristics of enzymes:

  1. Catalysts: Enzymes act as catalysts, which means they increase the rate of chemical reactions without being consumed in the process. They achieve this by lowering the activation energy required for a reaction to occur. In other words, enzymes make reactions happen faster and more efficiently.
  2. Specificity: Enzymes exhibit high specificity for their substrates. Each enzyme has a unique three-dimensional structure that allows it to bind to a specific substrate, which is the molecule that the enzyme acts upon. This specificity ensures that enzymes only catalyze the reactions they are intended for.
  3. Lock and Key Model: Enzyme-substrate binding can be described using the lock and key model. The enzyme’s active site, which is a region on the enzyme where the substrate binds, has a complementary shape to the substrate. This allows the substrate to fit into the active site like a key into a lock.
  4. Induced Fit Model: In addition to the lock and key model, the induced fit model describes the dynamic nature of enzyme-substrate binding. According to this model, the enzyme undergoes a conformational change upon substrate binding, resulting in a tighter fit between the enzyme and substrate. This conformational change helps facilitate the reaction.
  5. Reaction Specificity: Enzymes are specific not only to their substrates but also to the type of reaction they catalyze. Enzymes can be classified into different groups based on the type of reaction they facilitate. For example, hydrolases catalyze hydrolysis reactions, while oxidoreductases facilitate oxidation-reduction reactions.
  6. pH and Temperature Sensitivity: Enzymes have optimal pH and temperature ranges in which they function most effectively. Changes in pH and temperature outside these ranges can denature or alter the enzyme’s structure, leading to a loss of activity. This is why maintaining the right conditions is crucial for enzyme function.
  7. Regulation: Enzyme activity can be regulated to ensure that metabolic processes occur at the appropriate times and rates. Regulation can occur through various mechanisms, including allosteric regulation (where molecules bind to the enzyme at sites other than the active site), feedback inhibition (where the end product of a metabolic pathway inhibits an earlier enzyme), and post-translational modifications (such as phosphorylation or methylation).

In summary, enzymes are protein catalysts that increase the rate of chemical reactions in living organisms. They exhibit specificity for their substrates, can bind to them using the lock and key or induced fit models, and are specific to the type of reaction they catalyze. Enzyme activity is pH and temperature sensitive, and regulation mechanisms ensure proper control of metabolic processes.

Types of enzymes

According to the Enzyme Committee (EC) of the International Union of Biochemistry and Molecular Biology, enzymes are classified into 6 classes, according to the type of reaction they catalyze.

  • Oxidoreductases: are enzymes that catalyze oxidation-reduction reactions. For example: oxidases, reductases.
  • Transferases: they are responsible for catalyzing the transfer of a functional group between two compounds. For example: transaminases, dehydrogenases.
  • Hydrolases: These enzymes catalyze hydrolysis reactions, splitting a compound into two products. For example: peptidases, lipases.
  • Lyases: they are responsible for catalyzing the addition or elimination of a group without hydrolysis. For example: decarboxylases, deaminases.
  • Isomerases: Isomerases will catalyze the rearrangement of atoms within a molecule to form an isomer. For example: isomerases, epimerases, cycloisomerases.
  • Ligases: These enzymes catalyze the joining of two molecules using the energy of ATP. For example: synthetases, carboxylases.

Enzyme function

Enzymes are present in all the cells of our body and fulfill various important functions for the daily biological processes of humans and different living beings. Below we present some functions of enzymes:

They are responsible for reducing the activation energy of chemical reactions , which causes their activation. They are essential, since without them chemical reactions would take place slowly.

Some enzymes, such as proteases and amylases, play catalytic functions towards substrates that enter the digestive system of animals. That is, they help us break down those foods that we eat in our daily diet.

They are involved in signal transduction and regulation processes , such as phosphatases and kinases.

A set of enzymes acting simultaneously in a specific order will create a metabolic pathway . When a metabolic pathway occurs, the enzyme will take the product of the previous catalytic reaction as a substrate.

Structure of enzymes

Structurally, most enzymes are formed from globular proteins of very variable sizes . Some enzymes can be composed of chains of 62 amino acids, while there are also some that have up to 2,500 amino acids. From the assembly of these amino acids, the three-dimensional structure and specific functioning of the enzyme can be determined. The formation of an enzyme is the same as that of a protein, that is, the amino acids will be folded during translation to obtain the three-dimensional tertiary structure of an enzyme.

The structure of an enzyme has 2 sites:

A site for binding cofactors , which depending on whether or not the binding is carried out has two names. When the enzyme is alone, without the binding of a cofactor, it is called an apoenzyme and, on the contrary, when the cofactor is attached to the enzyme it is called a holoenzyme. Cofactors are important because they improve the interaction with the substrate and, therefore, much more efficient reactions occur.

We also find the active center where the union of the enzyme and the substrate will take place, where the enzyme-substrate complex is formed.

On the other hand, the structure of an enzyme can be denatured by denaturing agents, such as pH, temperature, ionic forces, etc. Denaturing agents act by destroying the tertiary structure of enzymes, converting them into their simplest form, that is, amino acids. Denaturation of enzymes causes the loss of their catalytic functions.

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