Amino Acids

Everybody has heard the term "amino acid" a million times, but really is an amino acid? Amino acids are the building blocks of proteins, which carry out many functions in organismic life. Some proteins act as catalysts, others serve for storage and transport, while still others are antibodies for our immune system. There are also numerous other functions that different proteins execute. The point is, amino acids are absolutely essential to cellular life. Chemically speaking, amino acids are carboxylic acids which have an amine group attached to it. The most general formula of an amino acid is RCH(NH2)COOH, which has the structure

(diagram)

There are more than 500 amino acids which occur in nature, but only 20 are used in all biological life known on earth. Of these 20, the most stable amino acids are the aliphatic acids: glycine, alanine, valine, isoleucine, and leucine. These have the structures


Of all of the amino acids generated in Miller's spark discharge experiment, glycine was the most abundant. This is how glycine was formed.

Formation of Glycine

1. CH20 + NH3 + HCN -> NH2CH2CN + H2O
Formaldehyde Ammonia Hydrogen Cyanide Ammonitrile Water

2. NH2CH2CN + 2H2O -> NH2CH2COOH + NH3
Ammonitrile Water Glycine Ammonia