Determination of Conformer-Specific Partition Coefficients in Octanol/Water Systems

2003 ◽  
Vol 46 (11) ◽  
pp. 2241-2245 ◽  
Author(s):  
Márta Kraszni ◽  
István Bányai ◽  
Béla Noszál
Keyword(s):  
Partition Coefficients ◽  
Water Systems

scholarly journals Mechanism of ligand binding to α1-acid glycoprotein (orosomucoid): correlated thermodynamic factors and molecular parameters of polarity

1995 ◽  
Vol 306 (2) ◽  
pp. 545-549 ◽  
Author(s):  
S Urien ◽  
Y Giroud ◽  
R S Tsai ◽  
P A Carrupt ◽  
F Brée ◽  
...  
Keyword(s):  
Binding Sites ◽  
Partition Coefficients ◽  
Water Systems ◽  
Hydrogen Bond Donor ◽  
Acid Glycoprotein ◽  
Number Of Binding Sites ◽  
Modelling Techniques ◽  
Polar Interactions ◽  
Polarity Parameters

Eight ligands were used in this study, four basic, three neutral and one acidic. Their binding to serum alpha 1-acid glycoprotein (orosomucoid) was measured at several temperatures, and the data were analysed together by a general model with three unknowns, number of binding sites, delta H0 and delta S0. The partition coefficients of the ligands were measured in octanol/water and heptane/water systems (log Poct. and log Phep.), and their molecular volumes were calculated by molecular modelling techniques. These structural properties allow determination of polarity parameters (delta log Poct.-hep., lambda oct. and lambda hep.) which encode in different proportions the various polar interactions between the solute and the aqueous and organic phases, i.e. hydrogen-bonding capacity and dipolarity/polarizability. This study shows that good correlations exist between delta H0 or delta S0 and polarity parameters, such that the enthalpic contribution to binding increases with increasing polarity of the ligands, mainly hydrogen-bond-donor acidity, whereas their entropic contribution to binding decreases.

Interphase distribution of 2-furylethylenes

1985 ◽  
Vol 50 (8) ◽  
pp. 1642-1647 ◽  
Author(s):  
Štefan Baláž ◽  
Anton Kuchár ◽  
Ernest Šturdík ◽  
Michal Rosenberg ◽  
Ladislav Štibrányi ◽  
...  
Keyword(s):  
Partition Coefficient ◽  
Partition Coefficients ◽  
Transport Rate ◽  
Phase System ◽  
Two Phase ◽  
Interphase Distribution ◽  
Distribution Kinetics ◽  
System 1 ◽  
Kinetics Of

The distribution kinetics of 35 2-furylethylene derivatives in two-phase system 1-octanol-water was investigated. The transport rate parameters in direction water-1-octanol (l1) and backwards (l2) are partition coefficient P = l1/l2 dependent according to equations l1 = logP - log(βP + 1) + const., l2 = -log(βP + 1) + const., const. = -5.600, β = 0.261. Importance of this finding for assesment of distribution of compounds under investigation in biosystems and also the suitability of the presented method for determination of partition coefficients are discussed.

scholarly journals Evidence for two asymmetric conformational states in the human erythrocyte sugar-transport system

1975 ◽  
Vol 145 (3) ◽  
pp. 417-429 ◽  
Author(s):  
J E Barnett ◽  
G D Holman ◽  
R A Chalkley ◽  
K A Munday
Keyword(s):  
Glucose Transport ◽  
Transport System ◽  
Human Erythrocyte ◽  
Partition Coefficients ◽  
External Medium ◽  
Sugar Transport ◽  
Conformational States ◽  
Glucose Transport System ◽  
Oil Water

6-O-methyl-, 6-O-propyl-, 6-O-pentyl- and 6-O-benzyl-D-galactose, and 6-O-methyl-, 6-O-propyl- and 6-O-pentyl-D-glucose inhibit the glucose-transport system of the human erythrocyte when added to the external medium. Penetration of 6-O-methyl-D-galactose is inhibited by D-glucose, suggesting that it is transported by the glucose-transport system, but the longer-chain 6-O-alkyl-D-galactoses penetrate by a slower D-glucose-insensitive route at rates proportional to their olive oil/water partition coefficients. 6-O-n-Propyl-D-glucose and 6-O-n-propyl-D-galactose do not significantly inhibit L-sorbose entry or D-glucose exit when present only on the inside of the cells whereas propyl-beta-D-glucopyranoside, which also penetrates the membrane slowly by a glucose-insensitive route, only inhibits L-sorbose entry or D-glucose exit when present inside the cells, and not when on the outside. The 6-O-alkyl-D-galactoses, like the other nontransported C-4 and C-6 derivatives, maltose and 4,6-O-ethylidene-D-glucose, protect against fluorodinitrobenzene inactivation, whereas propyl beta-D-glucopyranoside stimulates the inactivation. Of the transported sugars tested, those modified at C-1, C-2 and C-3 enhance fluorodinitrobenzene inactivation, where those modified at C-4 and C-6 do not, but are inert or protect against inactivation. An asymmetric mechanism is proposed with two conformational states in which the sugar binds to the transport system so that C-4 and C-6 are in contact with the solvent on the outside and C-1 is in contact with the solvent on the inside of the cell. It is suggested that fluorodinitrobenzene reacts with the form of the transport system that binds sugars at the inner side of the membrane. An Appendix describes the theoretical basis of the experimental methods used for the determination of kinetic constants for non-permeating inhibitors.

Solubilization of Amphiphilic Carboxylic Acids in Nonionic Micelles:  Determination of Partition Coefficients from pKaMeasurements and NMR Experiments

Langmuir ◽  
2007 ◽  
Vol 23 (21) ◽  
pp. 10463-10470 ◽  
Author(s):  
Laurence Dupont-Leclercq ◽  
Sébastien Giroux ◽  
Bernard Henry ◽  
Patrice Rubini
Keyword(s):  
Carboxylic Acids ◽  
Partition Coefficients
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