Enzymes: Types, Properties, Enzyme Action

Introduction

Enzymes are proteins that operate as biological catalysts. Catalysts help to increase the speed of chemical reactions. Anselme Payen, a French chemist, first discovered an enzyme in 1833. Enzymes work with molecules called substrates and convert them into different molecules called products. All biological processes in life forms are chemical changes, and enzymes regulate most of them. These procedures would not happen at all if enzymes weren’t present. This article covers enzymes—types and properties and enzyme action study material.

Classes of Enzymes

• Oxidoreductases

Oxidoreductases are enzymes that carry out reduction and oxidation reactions. Electrons are exchanged in the form of hydrogen ions and hydrogen atoms in these processes. They essentially work as hydrogen donors. They are also known as dehydrogenases and reductases. In special cases where oxygen is the acceptor, these enzymes are known as oxidases.Example:Glucose Oxidase

• Transferases

Transferases transfer functional groups from one molecule to another. For instance, alanine aminotransferase shuffles the alpha-amino group among alanine and aspartate.Example:Peptidyl transferase

• Hydrolases

These enzymes catalyse processes involving the hydrolysis process. They use water to break single bonds. Since they break the peptide down the proteins, some hydrolases act as digestive enzymes. As they move the molecule of water from one substance to another, hydrolases might also be considered transferases.Example:Lipases

• Lyases

These enzymes catalyse processes in which functional groups are introduced to molecules to break double bonds or remove functional groups to produce double bonds.Example:Citrate lyase

• Isomerases

These enzymes catalyse processes in which a functional group is transferred to a different place within the same molecule, resulting in a molecule that is an isomer of the original.Example:Alanine racemase

• Ligases

The function of these enzymes is the opposite of the hydrolases. Ligases build bonds by removing the water component, whereas hydrolases break down bonds by adding water. Several types of ligases are involved in the production of ATP.Example:Succinyl coenzyme A

Properties of Enzymes

Properties of enzymes can be divided into chemical, physical, and general properties. Chemical properties:

• Catalytic property: Enzymes act as biological catalysts. A small number of enzymes catalyse great quantities of chemicals. It signifies that enzymes have a great capacity for converting large amounts of a substrate to a product. Enzymes accelerate reactions while remaining unaffected by the reactions they catalyse
• Enzymes specificity: The specificity of enzymes to the reactions they catalyse is one of the qualities that make them valuable as diagnostic tools. Only a few enzymes have perfect specificity, which means they will catalyse only one reaction. There are four different forms of specificity in general
  • Absolute specificity: The enzyme will just catalyse one reaction at a time.
  • Group specificity: The enzyme will only operate on molecules with specific functional groups, like amino, phosphate, or methyl.
  • Linkage specificity: The enzyme will only work on a specific sort of chemical bond, regardless of the remainder of the molecule structure.
  • Stereochemical specificity: The enzyme has the ability to function on only one steric or optical isomer. 

Physical Properties

• Enzymes behave like colloids or high-molecular-weight substances
• At temperatures just below the boiling point of water, enzymes get damaged or inactivated
• Several enzymes in liquid media are inactivated at 60° Celsius
• Every enzyme has a temperature range for optimum action, which usually falls between 25 and 45° Celsius. When the temperature reaches 37° Celsius, enzymes become active, and when it reaches 60° Celsius, enzymes become inactive
• Dried enzymes extract can tolerate 100-120 ° Celsius and thus are known as thermolabile

Chemical  Properties

            Enzymes show the following chemical properties:

• Catalytic action:Enzymes act as catalysts and increase the rate of the reaction.They lower the activation energy of the reaction and increase the rate of the reaction
• Enzyme specificity:Enzymes are specific in their action. All enzymes cannot catalyse all reactions. Example:Enzyme sucrase catalyses  only hydrolysis of sucrose

General Properties

• Enzymes are proteins that start and speed up biological reactions
• The acidity of the media affects enzyme activity (pH specific). Every catalyst is most active at its optimum pH
• Enzymes are proteins in nature, although not all proteins are enzymes
• Enzymes reduce the energy required to activate a substance molecule, allowing the biochemical reaction to occur at body temperature, 37° Celsius
• Active sites are found in all enzymes and are involved in biological processes
• Enzymes isolated from some organisms can tolerate a high temperature condition. Thermal stability is the feature of such enzyme.Example:The enzyme Taq DNA Polymerase is a thermostable enzyme isolated from the bacteria Thermus aquaticus

Mechanism of Enzyme Action

An enzyme draws substrates towards its active site, catalyses the chemical process that produces products, and then dissociates the products (separate from the enzyme surface). The enzyme-substrate complex is the combination of enzymes and their substrates. 

The combination is termed a binary complex when a single substrate and an enzyme are involved and a ternary complex if two substrates and an enzyme are involved.

Hydrophobic and electrostatic forces attract the substrates to the active site, which are referred to as noncovalent bonds since they are physical rather than chemical.

Conclusion

Enzymes aid in the speeding up of biological reactions in our bodies—everything from respiration to digestion. Less of or too much of a specific enzyme might cause health issues. Some persons with chronic illnesses may require enzyme supplements to help their bodies function properly. Only use enzyme supplements under the guidance of a healthcare