LIPID MAPS® Partial Spectra Database (Partial Spectra DB)

Partial Spectra DB confidence stars:

•  have head group/important substructure identified
  • e.g., oxCE with cholesterol main fragments, and precursor formula indicates there is a FA 18:2;O
  • This lipid is annotated as: CE 18:2;O [2 stars]
•   have head group + some substructures identified, and the rest can be guessed from the formula
  • e.g., oxTG with one FA 18:1 and one FA 20:4;O with a water loss from FA 20:4;OH
  • From precursor formula, there should be an FA 16:0 but not identified (1 missing substructure)
  • This lipid is annotated as: TG 16:0_18:1_20:4;OH [3 stars]
•  All substructures are identified, although some positions/connections have uncertainties
  • e.g., oxPE with PE head group, one FA 16:0, and one FA 18:3;O with corresponding water loss
  • All main substructures are identified. But sn1/sn2, location of the C=C, cis/trans, R/S not clear
  • This lipid is annotated as: PE 16:0_18:3;OH [4 stars]

Above identifications are adapted from the Lipostar identification system (PMID: 28471643) and tuned to fit the partially annotated features. The number of stars is associated with the level of assigned substructures, the higher the number of stars, the more detailed lipid substructure annotated.