Enzymes are some of the most important class of proteins that catalyze many reactions occurring within the body. By the end of the reaction, the enzymes remain unchanged, although it may undergo many changes during the reaction. Their function includes not only catalyzing a reaction, but also controlling which reaction may take place at what time within the body. The function and structure are dependent on each other for executing a reaction. When the structure is minutely changed, it may cause a reaction to switch on or switch off.
Its function can be affected by other molecules like - inhibitors that decrease activity and activators that increase the activity of the enzymes. Function can also be affected by the temperature, chemical environment like pH and the concentration of the substrate.
Function and Structure
Enzymes are globular proteins that are made up of 62 amino acid residues to over 2,500 residues of animal fatty acid syntheses. Ribozymes or RNA enzymes are RNA based biological catalysts like ribosomes. They are larger than the substrate they act on. During a reaction, only 3 or 4 amino acids of the entire structure are involved in the catalysis. These regions where the catalytic residues bind to the substrate and carry out reactions is called the active site. Co-factors can also bind to the enzymes for carrying out reactions.
These are made up of long, linear chains of amino acids that are folded into a three-dimensional structure. A specific amino acid sequence produces a specific structure with different properties. Heating or chemical denaturants may cause the structure to denature and inactivate them. Denaturation can be reversible or irreversible depending on the enzyme.
What is the Function of Enzymes?
There are many functions that are carried out within living organisms. These are needed for signal transduction and cell regulation. They help in movement with myosin hydrolyzing ATP for generation of muscle contraction and moving molecules around a cell. Enzymes like amylase and protease are very important for breaking down large molecules like starch and proteins into smaller molecules.
Many enzymes work together to create a metabolic pathway. One uses the product of another as a substrate. Then at the end of the reaction, the product produced is used up by another enzyme to give rise to another product. Many pathways have more than one enzyme catalyzing the same reaction that leads to a very complex regulation. Here, one produces less products and others leads to high product production.
Specific functions help in categorizing each enzyme in different groups. They are classified into 6 groups that includes:
An enzyme may couple two different reactions . Some couple exothermic reaction with an endothermic reaction for helping an enzyme use the energy released by exothermic reaction to activate the endothermic reaction. Some are used commercially for synthesis of antibiotics. Also, they are added to washing powders, cleaners and detergents to breakdown fat stains on clothes. Some are added to meat tenderizers to break down proteins and making the meat softer.
How do Enzymes Function?
Enzymes lower the activation energy by temporarily combining with the chemicals that are involved in reactions to carry out their functions. These chemicals are substrates and each substrate is enzyme specific. The activation site of the enzyme will fit with only one kind of substrate. This is called enzyme substrate complex. Once the enzyme substrate complex is formed, the substrate is converted into a product. The structure is neither consumed or changed after the reaction is over.
Enzymes are very important for a living organism, as they carry out reactions at the cellular level. This helps in generation of energy that is ATP molecules and many other molecules needed for a survival of an organism.