Structure and Properties of Enzymes

Introduction

Enzymes are protein-based bio-catalysts that speed up biological reactions while having no effect on the final product’s nature. Enzymes, like catalysts, govern the rate and specificity of reactions without being consumed, but unlike catalysts, enzymes are only produced by living organisms. Enzymes, like catalysts, affect the rate of biochemical reactions so that they can occur at low temperatures. As a result, enzymes are known to reduce activation energy. Enzymes are frequently the catalysts of biological reactions.

Because yeast cells were the first to disclose enzyme activity in living organisms, the term enzymes is derived from the Greek word enzymes, which means “in yeast.”

In the year 1878, W. Kuhne created the term enzyme.

Structure of Enzymes 

  • Primary Structure : Amino acids are joined together in a linear chain by amide (peptide) bonds to form enzymes. This is the most important part of the building. Polypeptide or protein refers to the amino acid chain that results. The DNA sequence of the relevant gene specifies the exact order of amino acids in the protein

 

  • Secondary Structure : Each amino acid’s hydrogen in the amino group (NH2) and oxygen in the carboxyl group (COOH) can form a hydrogen bond, allowing amino acids in the same chain to interact. As a result, the protein chain can fold in two directions, yielding two secondary structures: the ⍺-helix and the ꞵ -sheet

 

  • Tertiary Structure : The protein can fold up further and obtain a three-dimensional structure as a result of the secondary structure folding up the 2D linear chain. The tertiary structure of the organism is as follows

 

Properties of Enzymes 

  • Physical Properties 

  • Chemical Properties 

  • General Properties 

Physical Properties 

  • In terms of physical qualities, enzymes are similar to colloids or high-molecular-weight compounds

  • Enzymes are damaged or inactivated at temperatures below the boiling point of water

  • At 60 degrees Celsius, most enzymes in liquid medium become inactive

  • Temperatures of 100 to 120 degrees Celsius, and even higher, can be tolerated by dried enzyme extracts. As a result, enzymes are thermostable

  • For optimum action, each enzyme requires a specific temperature range, which is usually between 25 and 45 degrees Celsius. Enzymes become inactive when the temperature hits 37 degrees Celsius, and when the temperature reaches 60 degrees Celsius, enzymes become inactive

Chemical Properties 

  • Catalytic Properties : Enzymes are biological catalysts with catalytic characteristics. The higher quantities of chemicals are catalyzed by a small number of enzymes. It signifies that enzymes have a great capacity for converting large amounts of substrate to product. Enzymes accelerate reactions while remaining unaffected by the reactions they catalyse

  • Enzyme specificity : Enzymes are extremely specific in nature, meaning that only one enzyme can catalyze a single process. Enzyme sucrase, for example, can exclusively catalyse sucrose hydrolysis

General Properties 

  • Enzymes are proteins that start and speed up biological reactions

  • The acidity of the media affects enzyme activity (pH specific). At a certain pH, each catalyst is most active. For example, pepsin has a pH of 2 whereas trypsin has a pH of 8.5. The pH of most internal enzymes is close to neutral

  • Enzymes have the ability to speed up a reaction in either way

  • All enzymes have active sites, which are engaged in biological activities

  • Enzymes are extremely unstable molecules that can only be dissolved in dilute glycerol, NaCl, and dilute alcohol

  • Enzymes are active when the temperature is just perfect

  • Enzymes are proteins in nature, although not all proteins are enzymes

  • Enzymes lower the amount of energy needed to activate a substance molecule, allowing the biochemical reaction to take place at body temperature, which is 37°C

Some other Important Properties of Enzymes 

  • Catalytic Property 

Enzymes have exceptional catalytic abilities.

They are only active in extremely little amounts.

It only takes a minimal amount of enzyme to convert a big number of substrates.

After the reaction, the enzymes are unaffected.

  • Specificity 

In nature, enzymes are incredibly specialised.

Only a specific substrate is acted upon by a certain enzyme.

Enzymes are also unique to a specific reaction type.

In some rare instances, the specificity may be insufficient.

  • Specificity of Bonds: It’s sometimes referred to as relative specificity. The enzyme is looking for a specific bond in this case. Peptidase, for example, is a Peptide Bond Specific enzyme

  • Absolute specificity is also known as substrate specificity

  • Only one substrate is acted upon by the enzyme

  • Structure specificity is another term for group specificity. The enzyme is specific to a subset of bacteria

  • Stereospecificity is another term for optical specificity. This is an enzyme’s maximum level of specificity. Not only is the enzyme particular to the substrate, but it is also specific to its optical configuration

  • Reversibility 

The majority of enzyme-catalyzed reactions can be reversed.

The reaction’s reversibility is determined by the cell.

There are separate enzymes for forward and reverse reactions in some circumstances.

  • Sensitiveness to Heat and Temperature 

Heat and temperature have a significant impact on enzymes.

At room temperature, an enzyme’s maximum activity occurs.

At very low temperatures, enzymes become inactive.

Conclusion 

The majority of enzymes are proteins having catalytic properties that are required for various processes to take place. A group of enzymes that are required for life’s survival carry out metabolic processes and other chemical reactions in the cell.

The enzymes, which react with a substance termed the substrate, are responsible for the first stage of the metabolic process. The products are created when enzymes transform substrates into other molecules.Because of their significance in supporting life processes, enzyme regulation has long been a significant component of clinical diagnosis. Except for the type of RNA catalysts known as ribozymes, all enzymes’ macromolecular components are made up of protein. Ribonucleic acid enzyme is the source of the word ribozyme.

 

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