Shorthand notation for Sterols (ST)

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Rules for the annotation

  • Shorthand notation: ST number of carbon atoms:number of double bonds.
  • Annotation at the lipid species level is based on natural sterols possessing 18, 19, 21, 24, or 27 carbons and at least one hydroxyl group at position 3.
  • Functional groups, including all hydroxyl groups, are shown after the number of double bonds separated by an underscore and followed by the number of groups if more than one.
  • Proven positions of functional groups are shown after the number of double bonds separated by a slash. Specific stereochemistry of functional groups is shown in square brackets, (R) and (S) configurations are preferred for side-chain stereochemistry and are given in italics in parenthesis.
  • In the case of fully proven structures of cholesterol and cholesteryl esters abbreviations FC and CE, respectively can be used. CE is followed by number of carbons:number of double bonds of the fatty acid esterified to the hydroxyl group at position 3.
  • In the case of unproven structures and other sterol esters (SE) the shorthand notation is used as above followed by slash number of carbons:number of double bonds of the fatty acid esterified to the hydroxyl group.
  • In the case of bile acids the shorthand notation is prefaced by A to indicate an acid and at the structure level the location of the acid group (CO2H) is indicated.
  • Precursor-ion scans reveal the presence of conjugating groups, i.e. taurine (T) or glycine (G), conjugated to the carboxylic acid group of bile acids through an amide bond, sulfuric acid (S) conjugated to a hydroxyl group through an ester bond, glucuronic acid (GlcA), N-acetylglucosamine (GlcNAc), and hexose (Hex) sugars assumed to be linked to a hydroxyl group through an acetal linkage.

Lipid class abbreviations

  • Sterols - ST
  • Steryl esters -SE
  • Free cholesterol - FC
  • Cholesteryl ester - CE
  • Bile acids:
    • Cholic acid - CA

**Chenodeoxycholic acid - CDCA **Deoxycholic acid - DCA **Ursodeoxycholic acid - UDCA **Hyodeoxycholic acid - HDCA **Lithocholic acid - LCA **Glycocholic acid - GCA **Taurocholic acid - TCA

Examples

$ m is the uncharged molecular mass

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