Protein

Basic structure

Proteins are compounds composed of carbon, hydrogen, oxygen, and nitrogen atoms. They differ from fats and carbohydrates by the fact that they contain nitrogen. These atoms form amino acids which are linked in a chain to form different proteins. Different protein form unique shapes which enable them to play vital roles in the body.

Amino Acid Structure

The side groups on amino acids vary from one amino acid to the next. Proteins are thus very complex. Proteins are made up of about 20 common amino acids. Amino acids are linked together by a peptide bond to from a chain.

Amino Acids

Amino acids can be grouped into essential and nonessential amino acids. Essential amino acids cannot be made in the body and therefore must be provided in the diet.

There are 9 essential amino acids that either the body cannot make, or cannot make in sufficient quantity to meet its needs. Therefore they must be provided in the diet.

There are some special circumstances when a non-essential amino acid becomes a conditionally essential amino acid. An example of this is tyrosine which the body normally makes from the essential amino acid, phenylalanine. However, if the diet fails to supply sufficient phenylalanine, or if the body for some reason is unable to make the conversion (e.g. in the inherited disease phenylketonuria, which we are all tested for at birth by a blood sample taken from a heel prick), then tyrosine becomes conditionally essential