15.2.5. Higher Unbranched Amino Acids

This version of 3AA-15.2.5 does not use the HTML table format.

The functional prefix 'amino' is included in the symbol as the letter 'A' and 'diamino' as 'A₂'. The trivial name of the parent acid is abbreviated to two letters, based, when possible, on the symbols for lipid nomenclature [19]. Unless otherwise indicated single groups are on C-2, two amino groups are in the 2 and terminal positions for monocarboxylic acids, and each is geminal with a carboxyl group for dicarboxylic acids. The location of amino groups other than these is shown by appropriate prefixes.

 Examples                                                        Symbol        Note

 [beta]-Alanine (3-aminopropanoic acid)                          [beta]Ala
 
 2-Aminobutyric acid (2-aminobutanoic acid)                      Abu
 
 2-Aminopentanoic acid (2-aminovaleric acid)                     Ape
 
 2-Aminohexanoic acid                                            Ahx
 
 6-Aminohexanoic acid                                            [epsilon]Ahx  i
 
 2-Aminoadipic acid (2-aminohexanedioic acid)                    Aad
 
 3-Aminoadipic acid (3-aminohexanedioic acid)                    [beta]Aad
 
 2-Aminopimelic acid (2-aminoheptanedioic acid)                  Apm 
 
 2,3-Diaminopropionic acid (2,3-diaminopropanoic acid)           A2pr or Dpr  ii, iii, iv
 
 2,4-Diaminobutyric acid (2,4-diaminobutanoic acid)              A2bu or Dab  ii
 
 Ornithine (2,5-diaminovaleric acid, 2,5-diaminopentanoic acid)  Orn 
 
 2,6-Diaminopimelic acid (2,6-diaminoheptanedioic acid)          A2pm or Dpm  ii, iii
 

(i) This symbol is recommended in place of the previous εAcp, in which 'cp' stood for caproic, which may be confused with capric and caprylic.

(ii) The previous edition of these recommendations [10] discouraged abbreviations starting 'D' for 'di' or 'T' for 'tri' or 'tetra'; because these letters were overused. We concur in preferring subscripts when these can be applied to well-known symbols, so that Me₂SO is preferable to DMSO, Me₃Si- to TMS-, and H₄ to TH. Nevertheless we are not convinced that 'A₂' easily suggests 'diamino', so alternative symbols are presented. In the table above the symbol should use a subscript 2.

(iii) 'Dap' should not be used as a symbol, since it could be construed to mean either diaminopropanoic acid or diaminopimelic acid.

(iv) 2,3-Diaminopropanoic acid can be regarded as 3-aminoalanine, and so may be symbolized by 'side-chain substitution' (3AA-17.3 below) as Ala(NH₂) or , but users should beware of the possibility that the former may be confused with Ala-NH₂ (3AA-17.1), the symbol for alaninamide.