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V G Ivkov

Publications and source records attributed to V G Ivkov.

23 records · Page 2Linked to original sources
PubMedDate not supplied

[Conformation of hydrocarbon chains in a lipid bilayer].

Based on the linear relationship between the entropy change deltaS during the phase transition and the length of he hydrocarbon chains of some lipids, the dependence of the probability of the trans--(pt) and gauche--(pg) conformation of the "averaged" methylene group of the chain on the increment deltas is deduced. Values of the probabilities for liquid n-alkanes, tri-glycerines and fatty acids are pt approximately equal to 0.6 and pg+ approximately equal to pg- approximately equal to 0.2, for liquid crystalline lecithin bilayers pt approximately equal to 0.8 and pg+ = pg- approximately equal to 0.1. From these data the average number of gaucheisomers per a plamitin chain in the dipalmitoylphosphatidylcholine molecule is estimated to be approximately 2.8-3.

Alkanes↗
PubMedDate not supplied

[Clusters in a liquid-crystalline lipid bilayer].

From analysis of the position and width of the diffuse maximum from X-ray scattering on hydrocarbon chains of phospholipid molecules, the average distance between neighbour chains in a bilayer and the values of interaction (correlation) radia were estimated. Comparison with the results of other methods applied shows that the cluster model of molecule packing in lipid bilayers explains the experimental data in the best way. The minimal dimensions of the clusters, average areas per molecule and approximate fraction of molecules in the clusters were estimated.

Chemical Phenomena↗
PubMedDate not supplied

[Mechanism of the fluorescent response of carbocyanine probe diS-C3-(5) to membrane potential change].

A method for estimation of constants of carbocyanine probe diS-C3-(5) partition between water and membrane phases was developed based on the analysis of fluorometric titration curves. The partition constants (K) of this dye were calculated (the ratio of dye mole fraction in membrane and water phases) for sarcoplasmic reticulum (SR) vesicles in sucrose K = (1.15 +/- 0.04) X 10(7) and salt K = (6.12 +/- 0.07) X 10(6) media and for the asolectine liposomes in salt medium K = (3.4 +/- 0.2) X 10(7). The probe partition between water and lipid phases was calculated for different membrane concentrations. Critical aggregation concentrations of probe in lipid phase were estimated to be approximately 8 mol. probe per 1000 mol. lipid for asolectine liposomes and approximately 9 mol. per 1000 mol. lipid for SR vesicles (both in salt medium), approximately 6 mol. per 1000 mol. lipid for SR vesicles in sucrose medium. On the basis of own and literature data a mechanism of voltage-sensitive probe response related to probe aggregation in membranes was suggested.

Animals↗