Leucines

As leucine is first summarizes the four isomeric amino acids leucine, isoleucine, tert- leucine and norleucine together. Compared with the four butanols they can be regarded as butyl-substituted glycines; thus represented all four variants. The number of maximum possible aliphatic amino acids having n carbon atoms in the side chain (without consideration of the stereoisomers ) is equal to the number of the ternary tree graph with n vertices. This results in the sequence of numbers 1 (for n = 0), 1, 1, 2, 4, 8, 17, ... For n = 4, so give 4 options. These are just realized by the amino acids mentioned above.

Leucine and isoleucine, among the proteinogenic amino acids, i.e., they are the building blocks of the proteins of living organisms and the genetic code encoding.

When we look to the stereoisomerism, then another 6 isomers should be expected: (a ) D- leucine, ( b ) D- isoleucine, ( c ) L -allo- isoleucine, ( d) D -allo- isoleucine, (e ) of D- tert-leucine and (f ) D- norleucine. They are described under each of the them corresponding amino acid articles.

The cycloleucine (1- aminocyclopentane -1 -carboxylic acid) can be considered as a derivative of the cyclic Norleucins. From this it differs inter alia by a lower order two hydrogen atoms molecular weight ( 129.16 g · mol -1). The defining structural element is a cyclopentane ring. The α - carbon atom is also not a stereogenic center; Cycloleucine is therefore not chiral.