All peptides and polypeptides are polymers of α-amino acids. There are 20 α-amino acids that are relevant to the make-up of mammalian proteins. Several other amino acids are found in the body free or in combined states. These non-protein associated amino acids perform specialized functions.
Amines
Amines are organic compounds and functional groups that contain a basic nitrogen atom with a lone pair. Amines are derivatives of ammonia, wherein one or more hydrogen atoms are replaced by organic substituents such as alkyl and aryl groups. Compounds with the nitrogen atom next to a carbonyl of the structure R-C(=O)NR2 are called amides and have different chemical properties.
Amino acids and DNA
DNA is a sequence of nucleotides. There are four nucleotides: adenine, thymine, cytosine, guanine. The exact sequence of these determines the code of each gene. When DNA is transcribed (the first step in expression of the gene), RNA is synthesized using this code. The RNA is a complementary copy of one strand of the DNA. The RNA leaves the nucleus and in the cytoplasm it is translated into a protein.
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