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The Working of Protein in the Human Body

Sep 2, 2011 | By Tina Andrews
The Working of Protein in the Human Body
Photo Credit Chad Baker/Photodisc/Getty Images

The scientists of the Human Genome Project estimate that all humans have approximately 20,000 to 25,000 genes, each containing the biological recipe for a different protein. The distinct shapes of various proteins enable them to perform specific functions. Proteins are categorized according to their role in the body, which include structural, enzymatic, immunologic, transportation and signaling functions. Your body also uses proteins to generate energy if your carbohydrate fuel supply is insufficient to meet your needs.

Structural Support

Proteins give your tissues physical structure. They serve as the matrix of your hair, nails, skin, muscles, bones, cartilage and organs. Specialized proteins in your muscles, heart, stomach, intestines and bladder also provide the mechanical components necessary for muscle contractions and movement. Structural and mechanical proteins are at work each time you take a breath, swallow a bite of food or dance to a favorite song.

Chemical Facilitation

Thousands of biochemical reactions occur throughout your body every moment of the day. Enzymes are proteins that act as biochemical catalysts--that is, they stimulate the occurrence and rate of chemical reactions. For example, digestive enzymes produced by your gastrointestinal system enable the chemical breakdown and absorption of food. Metabolic enzymes in your brain, muscles and other tissues facilitate energy production from sugars and fats. Synthetic enzymes catalyze the growth of your hair, skin and nails and the formation of new cells.

Infection Prevention

Immune system cells and proteins circulate throughout your body, searching for invading germs and killing those that breach your external defenses. Specialized immune system cells known as B cells produce proteins called antibodies, or immunoglobulins. These proteins stick to the surface of invading germs, tagging them for destruction by other immune system cells. Your immune system cells produce another group of proteins called cytokines. These proteins enable communication between various types of immune systems cells, which facilitates a coordinated attack when an infection poses a threat to your health.

Transportation

Proteins serve as carrier molecules for many chemicals in your bloodstream. Cholesterol and other blood fats, for example, require protein carriers to remain dissolved. The membranes that surround each of your cells also contain proteins that regulate the movement of chemicals into and out of your cells. Transport proteins are essential in maintaining chemical balance in your body.

Hormonal Signaling

Hormones are substances produced by one organ to control the activity of another organ or tissue. Many hormones are proteins, including insulin, growth hormone and thyroid stimulating hormone. The gonadotropins, which regulate reproductive function, are also protein hormones. Protein hormones, also known as peptide hormones, travel through your bloodstream to their tissue targets and bind to receptors, stimulating or halting specific activities within the target cells.

Energy Production

Although sugars are your body's preferred fuel, proteins can also be broken down to generate energy. During fasting or intense physical exercise, protein breakdown contributes a significant amount of energy to fuel your activities. This survival mechanism, however, can lead to a substantial loss of muscle mass during starvation or to a serious illness.

References

Article reviewed by Eric Althoff Last updated on: Sep 2, 2011

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