Proteins are highly multifunctional biological molecules responsible for most if not all biological processes that takes place in all living systems. DNA carries the code for the synthesis of proteins which is why DNA is often referred to as the blueprint of life.
Proteins are the topic of many research studies because if we can understand what they do and how they work, it can allow scientist to develop treatments and cures to a wide range of diseases. Many diseases such as cancer, diabetes, autoimmune diseases and neurodegenerative diseases develop due to a mutation in critical proteins.
Biological Functions of Proteins
Enzymes
Many proteins function as a biological catalyst. A catalyst speeds up chemical reactions and they are vital to sustain life. Almost all reactions in living systems are catalyzed by enzymes. Examples of enzymes are digestive enzymes that breakdown biological macromolecules.
- lipase – breaks down lipids into glycerol and fatty acids.
- amylase – breaks down complex carbohydrates (polysaccharides) into monosaccharides.
- protease – breaks down proteins into amino acids.
These enzymes are important as they break down large biological macromolecules into smaller components so they can be absorbed and used by our cells.
Transport
Transport proteins bind other molecules and transport them to other parts of the body. The most notable example is hemoglobin that binds and transports oxygen and carbon dioxide in red blood cells. This allows oxygen to be transported from your lungs when you breathe in to all cells in your body. Likewise it transports the carbon dioxide from your cells back to your lungs to be exhaled.
Structure and Support
Fibrous proteins provide structure and rigidity to cells.Common examples include keratin and collagen. Keratin is found in skin, hair and nails while collagen is found in your bones, tendons and ligaments.
Mechanical Work
Some proteins form assemblies to perform mechanical work such as the movement of flagella in bacterial cells, separation of chromosomes during mitosis and in the contraction of muscles.
Gene Expression
Some proteins are involved in DNA replication, translation and transcription which controls what genes are expressed and when.
Hormones
Some proteins are hormones which regulate biological activities. They act as chemical messengers that control and coordinate activities throughout the body. The most common example is insulin that is responsible for regulating blood glucose levels. When there is a problem with this hormone, diabetes develops and insulin has to be injected to prevent blood glucose levels from getting too high.
Immune function
Proteins such as antibodies defend our bodies against bacterial and viral infections. When we get infected by virus or bacteria, our bodies produce antibodies to bind and kill these foreign invaders.
Click on the links below to learn about protein structure
Click on the links below to learn about other biological macromolecules
References
2.) Principles of Biochemistry (4th Edition) by R.A Horton, L. A. Moran, G. Scrimgeour, M. Perry and D. Rawn. Copyright 2005. ISBN-13: 978-0131453067.
3.) Biology 2e by M. Clark, J. Choi and M. Douglas. Copyright 2018, ISBN-13 978-1-947172-52-4.