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Does it make sense to add together the concentrations of different stereospecifically numbered lipids?

I am trying to analyze a dataset that includes concentrations of lipids from an MS lipidomics analysis. I don't have the raw data or anything other than an Excel sheet showing samples and their lipid concentration. Many lipid names use the stereospecific naming convention (-sn1, -sn2) as well as naming isomers separately (-iso1, -iso2).

Because I am only interested in comparing species concentrations, would it be a good idea to add up all concentrations of the lipids that share a species but are different isomers or stereoisomers? For example, I would take LPE 22:6-sn2, with a (log scaled) concentration of 0.0012 together with LPE 22:6-sn1 with its concentration of 0.002, add them up, and say I have a total concentration for LPE 22:6 of 0.0032.

Would this be a valid way to go about the analysis? Or am I missing something important?

metabolomics lipidomics lipids mass-spectrometry
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updated by Ram Ram • written by Katia • Katia

1 answer

There's obviously no right or wrong answer per sé but I would advise against adding together (stereo)isomers. Most phospholipases and acyltransferases are highly specific to either the sn-1 or sn-2 position, so by combining such isomers you could miss on on real and meaningful effects

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written by bkleiboeker • bkleiboeker

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