This definition appears rarely
LIPID MAPS classification hierarchy Category (Example: Prenol lipids [LMPR]) Main class (Example: Isoprenoids [LMPR01]) Sub class (where applicable) (Example: C15 Isoprenoids (sesquiterpenes) [LMPR0103]) Level 4 class (where applicable) (Example: Bisabolane sesquiterpenoids [LMPR010306]) The LIPID MAPS LM_ID identifier The LIPID MAPS ID (LM_ID) is a unique identifier based on the classification scheme described above. The format of the LM_ID, outlined in the table below, provides a systematic means of assigning unique IDs to lipid molecules and allows for the addition of large numbers of new categories, classes and subclasses in the future. Currently, most LM_ID's have 12 characters, the exceptions being the molecules belonging to the level-4 classes of prenol lipids which have LM_ID's of 14 characters. The last four characters of the LM_ID comprise a unique identifier within a particular subset and are randomly assigned. In the case of generic structures containing "R" groups (such as 1,2-diacyl-sn-glycero-3-phosphocholine.