Functions of Proteins
Proteins are large organic molecules consisting of carbon, oxygen, hydrogen, nitrogen, sulfur and some also. Its basic components are the amino acids. Proteins play important roles for the organism, such as:
- Energy. When the supply of carbohydrates and fat from the diet is not enough to meet the energy needs amino acids from ingested proteins are oxidized to obtain energy as 1 gram of protein provides 4 kcal.
- Structural. It is their primary function, as many proteins are part of the body structures, such as keratin that forms part of the hair, skin and nails, collagen, an essential component of bones, tendons and cartilage and elastin, ligaments .
- Transportation. Some proteins transport specific ions or molecules from one organ to another. For example, the hemoglobin that carries oxygen-carrying albumin or free fatty acids, certain hormones …
- Regulatory. Other proteins are involved in regulating cellular activity, such as certain proteinaceous hormones such as insulin, growth hormone … The enzymes that catalyze cellular metabolic reactions and some neurotransmitters essential for the proper functioning of the nervous system.
- Defense. There are proteins that help defend the body by eliminating or protecting the body from the attack of certain microorganisms or foreign particles. This is the case of antibodies or immunoglobulins. There are also proteins involved in coagulation of the blood, such as fibrinogen, thrombin and other clotting factors.