Lipid_Calc

This application can be used to support lipid biochemists in their lipidomic investigations when electrospray ionization mass spectrometry is employed. LipidCalc can calculate the accurate mono-isotopic molecular weight of tens of thousands lipid molecular species as well as positive and negative molecular ions and several molecular ion adducts.

Fourteen (14) different lipid classes and subclasses can be chosen for precise m/z calculation. For those lipids containing fatty acyl groups (phospholipids, sphingolipids, cholesteryl esters, acyl CoA esters, wax esters, acyl carnitines, cardiolipins, and glycerides) a drop-down menu is provided from which one can select up to 30 different acyl groups to build the lipid class structure. The dropdown table of fatty acyl groups is ordered in biochemical frequency. The exact mono-isotopic molecular weight is calculated, and a table of common positive and negative molecular ion species can be viewed. The m/z is calculated at millimass unit accuracy. The ions are calculated either as [M+H]+, [M-H]-, or common ion adducts with alkali metals or organic acid anion adducts. Fatty acids and fatty acid lipid mediators such as prostaglandins and leukotrienes are also included along with common lipid mediator metabolites.

For those lipids, such as steroids and sterols which are unique molecular species, over 28 examples are provided which can also be view as monoisotopic molecular weight, positive or negative ions. The four common bile acids can be calculated either as glycine or taurine conjugates, or as free bile acid. Several uncommon lipids such as dolichols, prenols, and lipid soluble vitamins such as vitamin A, D3, E, K, as well as coenzyme Q are included. The largest number of molecular species is derived for cardiolipins which include four acyl groups for which over 50,000 individual molecular species are theoretically possible.