"Bulk" Structure Searches
— Documentation

Creation of the LIPID MAPS® Database of computationally-generated "bulk" Lipid Species (COMP_DB)

The LIPID MAPS® Database of computationally-generated "bulk" Lipid Species (COMP_DB) is a virtual database composed of major classes of lipid species, generated from list of commonly occuring acyl/alkyl chains (see below) These "bulk" lipid species indicate the number of carbons and number of "double bond equivalents" (DBE), but not chain positions or double bond regiochemistry and geometry. The concept of a double bond equivalent unites a range of chemical functionality which gives rise to isobaric features by mass spectometry. For example a chain containing a ring results in loss of 2 hydrogen atoms (compared to a linear structure) and thus has 1 DBE since the mass and molecular formula is identical to a linear structure with one double bond. Similarly, conversion of a hydroxyl group to ketone results in loss of 2 hydrogen atoms, therefore the ketone is assigned 1 DBE. Where applicable, the number of oxygen atoms is added to the abbreviation, separated by a semi-colon. Oxygen atoms in the class-specific functional group (e.g. the carboxylic acid group for fatty acids or the phospholcholine group for PC) are excluded. In the case of sphingolipids, all oxygen atoms apart from the amide oxygen are included, in order to discrminate, for example, between 1-deoxyceramides (O), ceramides (O2) and phytoceramides (O3). A comprehensive list of examples is shown below.

Commonly occuring acyl/alkyl chains used to create COMP_DB

The acyl/alkyl chains used to create the COMP_DB database of glycerophospholipids, glycerolipids, sphingolipids, acyl carnitines, acyl CoA's, cholesteryl esters and wax esters:
10:0 12:0 13:0 14:0 14:1 15:0 15:1 16:0 16:1 17:0 17:1 17:2 18:0 18:1 18:2 18:3 18:4 19:0 20:0 20:1 20:2 20:3 20:4 20:5 21:0 22:0 22:1 22:2 22:4 22:5 22:6 23:0 24:0 24:1 24:2 24:3 24:4 24:5 25:0 25:1 26:0 26:1 26:2 26:3 26:4 26:5 26:6 27:0 27:1 27:3 28:0 28:1 28:2 28:3 28:4 28:5 28:6 29:0 29:2 29:3 30:0 30:1 30:2 30:3 30:4 30:5 30:6 31:0 32:0 32:1 32:4 32:5 32:6 33:0 34:0 34:4 34:5 34:6 O-16:0 O-18:0 O-20:0 P-16:0 P-18:0 P-20:0

The acyl chains used to create the COMP_DB database of fatty acids: (OH:hydroxyl, Ke: keto(oxo), Ep:epoxy)
(only searched in negative ion mode) 10:0 10:1 10:2 10:3 10:4 10:5 11:0 11:1 11:2 11:3 11:4 11:5 12:0 12:1 12:2 12:3 12:4 12:5 12:6 13:0 13:1 13:2 13:3 13:4 13:5 13:6 14:0 14:1 14:2 14:3 14:4 14:5 14:6 15:0 15:1 15:2 15:3 15:4 15:5 15:6 16:0 16:1 16:2 16:3 16:4 16:5 16:6 17:0 17:1 17:2 17:3 17:4 17:5 17:6 18:0 18:1 18:2 18:3 18:4 18:5 18:6 19:0 19:1 19:2 19:3 19:4 19:5 19:6 20:0 20:1 20:2 20:3 20:4 20:5 20:6 21:0 21:1 21:2 21:3 21:4 21:5 21:6 22:0 22:1 22:2 22:3 22:4 22:5 22:6 23:0 23:1 23:2 23:3 23:4 23:5 23:6 24:0 24:1 24:2 24:3 24:4 24:5 24:6 25:0 25:1 25:2 25:3 25:4 25:5 25:6 26:0 26:1 26:2 26:3 26:4 26:5 26:6 27:0 27:1 27:2 27:3 27:4 27:5 27:6 28:0 28:1 28:2 28:3 28:4 28:5 28:6 29:0 29:1 29:2 29:3 29:4 29:5 29:6 30:0 30:1 30:2 30:3 30:4 30:5 30:6 31:0 31:1 31:2 31:3 31:4 31:5 31:6 32:0 32:1 32:2 32:3 32:4 32:5 32:6 33:0 33:1 33:2 33:3 33:4 33:5 33:6 34:0 34:1 34:2 34:3 34:4 34:5 34:6

The acyl chains used to create the COMP_DB database of cardiolipins:
12:0 14:0 14:1 16:0 16:1 18:0 18:1 18:2 18:3 20:0 20:1 20:2 20:3 20:4 20:5 22:0 22:1 22:2 22:4 22:5 22:6 24:0 24:1 26:0 26:1