"Real time" molecular dynamics simulations of water permeation through human aquaporin-1 (AQP1) and the bacterial glycerol facilitator GlpF are presented. We obtained time-resolved, atomic-resolution models of the permeation mechanism across these highly selective membrane channels. Both proteins act as two-stage filters: Conserved fingerprint [asparagine-proline-alanine (NPA)] motifs form a se...

The selective separation of aromatics (benzene, toluene and p-xylene, BTX) from aliphatic (n-heptane) is investigated using simple permeation and facilitated transport emulsion liquid membrane mechanism. The separation performances, represented by the permeation rate and separation factor, are analyzed systematically by varying the operating parameters. One of the major obstacles to the applica...

Aquaporins and aquaglyceroporins form a family of pore proteins that facilitate the efficient and selective flux of small solutes across biological membranes. We studied the selectivity of aquaporin-1 (AQP1) and the bacterial glycerol facilitator, GlpF, for O(2), CO(2), NH(3), glycerol, urea, and water. Using molecular dynamics simulations, we calculated potentials of mean force for solute perm...

Borneol and menthol were two terpenes wildly used as penetrate enhancer in 14 transdermal drug delivery. To explore their penetration enhancement effect towards hydrophilic 15 drug, 5-FU was selected as model drug. A method combined vitro permeation studies and coarse 16 grain molecular dynamics was used to investigate their penetration enhancement effect towards 17 5-FU. As a result, although ...

Potassium channels selectively conduct K(+) ions across cellular membranes with extraordinary efficiency. Their selectivity filter exhibits four binding sites with approximately equal electron density in crystal structures with high K(+) concentrations, previously thought to reflect a superposition of alternating ion- and water-occupied states. Consequently, cotranslocation of ions with water h...

Synopsis The effect of several variables on the in vitro permeation of urea through hairless mouse skin has been studied in order to determine the causes of an increasing permeability phenomenon found in studies with a range of hydrophilic compounds. The permeation of urea increased for a period of approximately 100 h after which a steady state permeation pattern was observed for approximately ...