LIPID MAPS® abbreviations for glycerolipids (GL)

The LIPID MAPS® glycerolipid abbreviations (MG,DG,TG) are used here to refer to species with one, two or three radyl side-chains, respectively, where the structures of the side chains are indicated within parentheses in the 'Prefix(sn1/sn2/sn3)' format (e.g. TG(16:0/18:1(9Z)/18:0). Acyl chains are assumed by default. The alkyl ether linkage is represented by the 'O-' prefix, e.g. DG(O-16:0/18:1(9Z)/0:0), whereas the 1Z-alkenyl ether (Plasmalogen) linkage is represented by the 'P-' prefix, e.g. and DG(P-14:0/18:1(9Z)/0:0).

For Diradylglycerols and Triradylglycerols, it is not always possible to experimentally determine the exact position of radyl groups on the glycerol group. For Diradylglycerols with two different radyl groups, two different structural isomers exist. For Triradylglycerols with three different radyl groups, six different isomers exist.

Instead of drawing all possible structural isomers explicitly for Diradylglycerols and Triradylglycerols, the LIPID MAPS® abbreviation scheme supports the isomeric specification. A suffix containing 'iso' along with the number of possible isomers is appended to the abbreviation (e.g. [iso2],[iso6]) and a single unique LM_ID is assigned. The structure assigned to the LM_ID corresponds to the radyl substitution shown in the abbreviation. An option is provided to display the other isomers in the group.

The [rac] designation refers to racemic mixtures due to substitution at the sn1 and sn3 positions of glycerol.