Alkanes are not innocuous vehicles for hydrophobic reagents in membrane studies.
Alkanes (C6-C16) are often used as vehicles for hydrophobic reagents, e.g. long-chain ceramides, in cell biology studies. It is generally understood that they are inert solvents, particularly when added in small volumes. However, simple calculations show that, under standard experimental conditions in cell studies, alkane: phospholipid molar ratios in excess of 1000:1 may be found. Even at much smaller ratios (close to 1:1) our studies with liposomes show that alkanes induce vesicle aggregation. Differential scanning calorimetry shows marked changes in both the gel-fluid and the lamellar-hexagonal transitions. Alkanes inhibit bacterial sphingomyelinase when acting on large unilamellar vesicles, and activate bacterial phospholipase C under the same conditions. Thus, the use of alkanes in cell studies requires strict control experiments to avoid artefactual results.
Urbina
Patricia
P
Unidad de Biofísica (Centro Mixto CSIC-UPV/EHU), and Departamento de Bioquímica, Universidad del País Vasco, Aptdo. 644, 48080 Bilbao, Spain.
Alonso
Alicia
A
Contreras
F-Xabier
FX
Goñi
Félix M
FM
López
David J
DJ
Montes
L-Ruth
LR
Sot
Jesús
J
D000473:Alkanes / Q000737:chemistry* / Q000494:pharmacology*; D002152:Calorimetry, Differential Scanning / Q000379:methods; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D008567:Membranes, Artificial; D012680:Sensitivity and Specificity; D013108:Sphingomyelin Phosphodiesterase / Q000037:antagonists & inhibitors / Q000737:chemistry; D013696:Temperature; D013997:Time Factors; D010738:Type C Phospholipases / Q000737:chemistry / Q000187:drug effects
D000473:Alkanes; D008567:Membranes, Artificial; D010738:Type C Phospholipases; D013108:Sphingomyelin Phosphodiesterase