Solubility limits of cholesterol, lanosterol, ergosterol, stigmasterol, and β-sitosterol in electroformed lipid vesicles

Abstract

Here we use nuclear magnetic resonance to measure the solubility limit of several biologically relevant sterols in electroformed giant unilamellar vesicle membranes containing phosphatidylcholine (PC) lipids in ratios of 1:1:X DOPC:DPPC:sterol. We find solubility limits of cholesterol, lanosterol, ergosterol, stigmasterol, and β-sitosterol to be 65-70%, ~35%, 30-35%, 20-25%, and ~40%, respectively. The low solubilities of stigmasterol and β-sitosterol, which differ from cholesterol only in their alkyl tails, show that subtle differences in tail structure can strongly affect sterol solubility. Below the solubility limits, the fraction of sterol to PC-lipid in electroformed vesicles linearly reflects the fraction in the original stock solutions used in the electroformation process.

Effect of Sterol Structure on the Physical Properties of 1-Palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine Membranes Determined Using 2H Nuclear Magnetic Resonance

“…Next we compare our results on sterol ordering ability in POPC with the findings of Stevens et al 14 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 22 DOPC/DPPC(1:1) 14 (Table. 1 …”

Differential Effect of Plant Lipids on Membrane Organization

“…The DOPC (T m ϭ Ϫ20°C)/DPPC (T m ϭ 41°C) lipid mixture, which has been widely used in the literature to characterize the physical properties of the membrane model system (11,14,83,108,109), exhibits, at temperatures below 45°C, an L o and L d phase coexistence (83). Performing our experiments at 22°C and minimizing temperature fluctuations, we actually favored a long time equilibrium formation of L o and L d phase separation, allowing us to focus our study on the structuring effect of plant lipid on L o and L d phase partitioning.…”

Anti-diabetic potential of Urena lobata leaf extract through inhibition of dipeptidyl peptidase IV activity

“…Non-polar compounds such as stigmasterol, b-sitosterol and gossypetin could be extracted in water solvent even though in small amount. When the water is boiled, their polarity will decrease so that it could be extracted from semi-polar until non-polar compounds [27] .…”

“…First, as a membrane-spanning protein, it binds adenosine deaminase and when activated, conveys intracellular signals independent of its enzymatic function via dimerization and activation of intracellular signaling pathways. The signaling properties of membrane-associated CD26 have been most extensively characterized in T cells [27]. The second principal biological activity of CD26 (DPP-IV) is its enzymatic function.…”

“…The second principal biological activity of CD26 (DPP-IV) is its enzymatic function. The enzymatic activity of CD26 is exhibited by the membranespanning form of the molecule, and by the slightly smaller circulating soluble form [27,28] .…”