Protein functions

The proteins are used for a multitude of functions in the cells and in the tissues. The function of a protein is determined by two factors: the aminoacids sequence and the folding of the polypeptide chain. Thinking about this, a persistent faulty incorporation of one incorrect aminoacid in the polypeptide chain can cause a severe disruption of the protein function, being the basis of many genetic diseases.

The main protein functions in our body are:

1. Building material. They got an important structural role outside and inside the cell. The main structural protein is collagen, which is also the most abundant, being found in skin, tendons, cartilage, bone, connective tissue and giving structure and strength to tissues and cell. Defects in collagen synthesis can result in brittle bones (osteogenesis imperfecta). 

2. Enzymes. Are defined as proteins that speed up a biochemical reaction, having a catalyst function, by lowering the activation energy barrier needed to be overcome for a reaction to happen. Every cell has more than one thousand enzymes responsible for different reactions (like those required to generate energy by breaking down glucose or fatty acids).

3. Transporters (totally unrelated to Jason Statham movie). They offer assistance with the transport of different molecules across the cell membrane (in and out).

4. Hormones. They are messengers circulating via blood stream, released from a specific tissue into the blood to signal something to distant tissues ( like the insulin released by pancreas to reach muscle and fat tissue to promote glucose uptake). Chemically speaking, the hormones are either polypeptides or steroids.

5. Antibodies. They are involved in defending the body against pathogens such are viruses and bacteria, and are called immunoglobulins, secreted by plasma cells, with the role of creating an immune system.

6. Regulation of fluid balance. They are taking care of the water being appropriately distributed across the blood stream (intravascular), in the space between the cells (intercellular) and inside the cells (intracellular).

Next post will be about protein turnover and nitrogen balance, and maybe some more extra bits. Have a nice day. See you soon.