Cholesterol phosphatidylcholine effect

Kusumi, A., W. K. Subczynski, M. Pasenkiewicz-Gierula, J. S. Hyde, and H. Merkle. 1986. Spin-label studies on phosphatidylcholine-cholesterol membranes Effects of alkyl chain length and unsaturation in the fluid phase. Biochim. Biophys. Acta 854 307-317. 

The effect of hemolysis on the determination of Mn-SOD levels by ELISA was examined. The lysis of erythrocytes was observed to have no effect. Because erythrocytes do not contain any Mn-SOD, the problems encountered with Cu,Zn-SOD do not occur when serum Mn-SOD levels are measured. The effects of jaundice and lipids were also examined by adding substances such as ascorbic acid, bilirubin, cholesterol, phosphatidylcholine, and triglycerides. None of the above substances affected the detection of Mn-SOD in sera. 

Discuss the effects on the lipid phase transition of pure dimyris-toyl phosphatidylcholine vesicles of added (a) divalent cations, (b) cholesterol, (c) distearoyl phosphatidylserine, (d) dioleoyl phosphatidylcholine, and (e) integral membrane proteins. 

FIGURE 1 Effect of (sequential) extrusion of MLV dispersions through polycarbonate membrane filters (Unipore) with pore sizes of 1.0, 0.6, 0.4, 0.2, and 0.1 ym on the mean liposome diameter. DXR-containing MLV (phosphatidylcholine/phosphatidylserine/ cholesterol 10 1 4) mean diameter of nonextruded dispersion about 2 ym pH 4. Mean particle size determined by dynamic Light scattering (Nanosizer, Coulter Electronics). (From Crommelin and Storm, 1987.)... 

FIGURE 3 Effect of the amount of cholesterol on the particle size. Phosphatidylcholine/cholesterol liposomes were prepared by the octyl glucoside dilution technique. The begin concentration of the mixed micelles was 150 mM octyl glucoside and 10 mM phosphatidylcholine in 10 mM tris(hydroxymethyl)aminomethane and 0.9% NaCl, pH 7.4. Dilution was performed with an automatic titration unit at a dilution rate (= dilution factor, relative to the initial volume, per unit of time) of 0.026 sec"l ( a and ) or 0.69 sec l ( and o). Mean diameters after dilution and ) and after filtration ( L and q) are repi sented. (Adapted from Jiskoot et al, 1986a.)... 

Yeagle, P. L. Hutton, W. C. Huang, C.-H. Martin, R. B., Headgroup conformation and lipid-cholesterol association in phosphatidylcholine vesicles A 31P 1H nuclear Over-hauser effect study, Proc. Natl. Acad. Sci. 72, 3477-3481 (1975). 

Van Duyl, B. Y., Ganchev, D., Chupin, V., de KruijfF, B. and Killian, J. A. Sphingomyelin is much more effective than saturated phosphatidylcholine in excluding unsaturated phosphatidylcholine from domains formed with cholesterol. FEES Lett. 547 101-106,2003. 

Handa, T., Eguchi, Y., and Miyajima, K. (1994) Effects of cholesterol and cholesteryl oleate on lipolysis and liver uptake oftriglycerides/phosphatidylcholine emulsions in iBIsarm. Res., 11 1283-1287. 

Muramatsu, K., et al. 1994. Effect of soybean-derived sterol and its glucoside mixtures on the stability of dipalmitoyl-phosphatidylcholine and dipalmitoylphosphatidylcholine/cholesterol liposomes. Int J Pharm 107 1. 

The effects of cholesterol and cholesterol-derived oxysterols on adipocyte ghost membrane fluidity has been studied. It has been found that cholesterol and oxysterols interact differently with rat adipocyte membranes. Cholesterol interacts more with phosphatidylcholine located at the outer lipid bilayer whereas, for example, cholestanone seems to interact more with phospholipids located at the inner layer... 

Stockton, G. W. and Smith, I. C. P. (1976). A deuterium NMR smdy of the condensing effect of cholesterol on egg phosphatidylcholine bilayer membranes. 1. Per-deuterated fatty acid probes. Chem. Phys. Lipids 77 251. 

McMullen TPW, Lewis RNAH, McElhaney RN. Differential scan- 45. ning calorimetric study of the effect of cholesterol on the thermotropic phase behavior of a homologous series of linear saturated phosphatidylcholines. Biochemistry 1993 32 516-522. 

Marsh (38) has listed several measured values of the elastic moduli of lipid bilayers. Typically, the area compressibility moduli are in the range of 200-250 mNm for fully hydrated symmetric bilayers in the L phase prepared from phosphatidylcholines, and they are not very dependent on the degree of saturation of the acyl chains. Cholesterol has a significant effect on the area compressibility modulus of a bilayer. Thus, AT A for bilayers of l-stearoyl-2-oleoylphosphatidylcholine (SOPC) increases from 235 mN m in the absence of cholesterol (La liquid-disordered phase) to 640 mN m in bilayers... 

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