Friday, September 6, 2019

Functions of Lysosome | Lysosomal Enzymes and Their Functions

What is Lysosomes?
Lysosomes are small sac-like structures surrounded by a single membrane and containing strong digestive enzymes that can break down food and engulfed viruses or bacteria. Lysosomes are membrane-bound organelles found within cells. Lysosomes are also known as a suicide sac in the cell.
Fig: Lysosomes
Shape and Size of Lysosomes:
Lysosomes are like the stomach of the cell and they digest waste and superfluous cell fragments. Lysosomes are usually a small sac-like spherical structure. It measures about 0.5-1.0 ┬Ám in diameter.

Number of Lysosomes:
Number of lysosome present in a cell- 

Range → 50 to 1,000 Lysosomes/cell
There are 50 to 1,000 lysosomes per mammalian cell, but a single large lysosome called the vacuole in fungi and plants.

Different Lysosomal Enzymes and Their Functions:
Lysosomes contain so many digestive enzymes and they digest nutrient molecules. They contain about 45 enzymes that are grouped into six main categories:

1. Nucleases:
Nucleases are important enzymes that hydrolyze nucleic acids.

2. Proteases:
Proteases include enzymes like collagenase and peptidases that convert protein into amino acid.

3. Glycosidases:
Glycosidases convert polysaccharides into monosaccharides. For instance, they convert lactose into glucose and galactose.

4. Phosphatases:
Phosphatases are enzymes that act on organic phosphate compounds to release phosphate.

5. Lipase:
Lipases that act on lipids to produce acids and alcohol.

6. Sulphatases:
Sulphatases are enzymes that act on organic compounds to release sulfates.

Main Functions of Lysosome:
All the functions of lysosome have pointed out in the following:
  • The main function of lysosomes is to help with cell metabolism by ingesting and dissolving unwanted parts of the cell, cell debris or foreign substances that have entered the cell.
  • Acts as autophagic vesicles of the cell.
  • Acts as scavengers of the cell.
  • The digestive enzymes of their acidic interior break down large structures and molecules into simple components, and they then return the products to the cell for further use or disposal.
  • Lysosomal enzymes are synthesized by Endoplasmic Reticulum (ER).
  • The enzymes are passed on to the Golgi apparatus where the lysosomes are produced.
  • Lysosomes use the acid hydrolases from the endoplasmic reticulum to digest complex proteins and organelles that are no longer needed.
  • The lysosomes essentially act as the cell's digestive system.