Which lipid is absent in most prokaryotic and plant membranes?
Evolutionary lipidomics reveals sterol distribution discontinuous across domains life reflecting oxygen dependent biosynthesis pathway complexity. Eukaryotes animals synthesize cholesterol via HMGCoA reductase squalene monooxygenase epoxidase lanosterol fourteen demethylase CYP51 DHCR enzymes pathway requiring molecular oxygen maintaining thirty to forty percent plasma membrane buffering fluidity organizing rafts signaling. Fungi use ergosterol additional double bonds methyl group phytosterol plants stigmasterol sitosterol campesterol from cycloartenol SMT sterol methyltransferase modification
Ref: Nes WD, Chem Rev 2011, Sterol biosynthesis diversity bacterial absence cholesterol and hopanoids.
