Amino acids are the building blocks of protein and can be defined as an organic molecule made up of amine and carboxylic acid functional groups. Amino acids are not only responsible for the production of all the body's enzymes, catalyze most of the reactions in living cells, but they also play a key role in normalizing moods, concentration, aggression, attention, sleep and virtually all other cellular process.
Amino acids come from protein rich sources such as meat, fish, dairy products, and vegetables such as peas and beans. After protein is consumed, it is broken down by the digestive enzymes into amino acids. Then, individual amino acids are used to create necessary body proteins and enzymes. The body, through assimilation of amino acids, produces over 50,000 proteins and over 15,000 enzymes.
The 23 amino acids that are found within proteins convey a vast array of chemical versatility. The precise amino acid content, and the sequence of those amino acids, of a specific protein, is determined by the sequence of the bases in the gene that encodes that protein.
The chemical properties of the amino acids of proteins determine the biological activity of the protein. In addition, proteins contain within their amino acid sequences the necessary information to determine how that protein will fold into a three dimensional structure, and the stability of the resulting structure.
Humans do not have all the the enzymes required for the biosynthesis of all of the amino acids. Essential amino acids, also called limiting amino acids, are those that can not be produced in our body and there fore have to be obtained from food sources.
There are 9 essential and some semi-essential amino acids. Even at non-athletic levels of activity, the list of conditionally indispensabla amino acids has grown to 6.
Failure to obtain enough of even 1 of the essential amino acids, those that we cannot make, results in degradation of the body's proteins-muscle and so forth-to obtain the one amino acid that is needed.
Unlike fat and starch, the human body does not store excess amino acids for later use-the amino acids must be in the food every day.
The 13 amino acids that we can produce are alanine, asparagine, aspartic acid, cysteine, glutamic acid, glutamine, glycine, proline, serine, hidroxy-lysine, hydroxy-proline, tyrosine, gamma-carboxy-glutamic acid. Semi-esential amino acid is the arginine (essential for the young, but not for adults) and the essential amino acids are, histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine.
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Amino acids 
