What are Proteins?
Proteins make up about 15% of the mass of the average person. Proteins
are essential for life. They are the major source of building materials
for muscle, blood, skin, hair, nails, enzymes, hormones, and antibodies.
Proteins can serve as an energy and heat source for the body and are needed
for proper elimination of waste materials through urine.
Proteins belong to a class of organic compound called polyamides. A protein
is a molecule that consists of a chain of amino acids. There are 20 different
amino acids to choose from, and the genetic information in our DNA determines
how they're put together. A single protein consists of hundreds of amino
acids, all folding into a structure with a specific shape.
Proteins are involved in practically every function performed by a cell.
Main protein functions in the body:
- Enzymatic proteins - these are proteins that help to promote a chemical
reaction. Enzymes carry out almost all of the thousands of chemical
reactions that take place in cells. They also assist with the formation
of new molecules by reading the genetic information stored in DNA.
- Transport proteins - are involved in transporting other substances.
- Structural proteins are very important for support. They provide structure
and support for cells. On a larger scale, they also allow the body to
- Storage proteins store amino acids.
- Hormonal proteins coordinate the bodily activities.
- Receptor proteins are built into the membrane of a nerve cell and
they detect chemical signals released by other nerve cells.
- Contractile proteins are very important in movement. Actin and myosin
are responsible for the movement of muscles. Contractile proteins are
reponsible for the undulations of cilia and flagella.
- Defensive proteins protect against diseases. Antibodies combat bacteria
Meat, poultry, fish, milk, eggs and cheese are considered complete sources
of protein. Nuts, legumes, navy beans, peas, soybeans, grains (especially
unrefined), potatoes are also good sources of protein.
Soy protein is derived from the soybean plant and a good,
although incomplete, source of protein. Soy protein products come in various
concentrations and are available alone or in combination with carbohydrate
and fatty acid constituents. Soy products are relatively inexpensive.
Whey protein is obtained during the processing of milk
to cheese. Whey is a complete protein. Although an excellent protein source
whey is not better than meats or dairy products. Whey protein is generally
more expensive than soy based protein.