Protein

Protein describes a group of organic compounds consisting of the elements:

• carbon
• hydrogen
• nitrogen
• oxygen

Sulphur and phosphorous may also be present. These elements combine into the basic building blocks of proteins, amino acids. Amino acids combine to form chains of increasing length. The nature and number of amino acids in the chain determines higher levels of structure: folding and twisting of the chain, association with other chains and prosthetic groups. In turn, structure determines function.

Protein has a diverse range of functions:

• structural elements e.g. cell membrane transporters, collagen
• transport e.g. haemoglobin
• metabolism e.g. enzymes and hormones
• energy source

A generalized deficiency of protein intake can lead to increased susceptibility to disease. Conversely, many diseases lead to protein deficiency which may present with the symptoms of hypoalbuminaemia.