Thermotropic behaviour of phospholipid vesicles reconstituted with rat liver microsomal cytochrome P-450

Ахрем, А. А.; Andrianov, V.T.; Bokut, S. B.; Luka, Zigmund; Kissel, M.A.; Skornyakova, T.G.; Kisselev, Pyotr

doi:10.1016/0005-2736(82)90533-8

Cited by 16 publications

(6 citation statements)

References 38 publications

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“…The asymmetry of calorimetric transitions is sometimes described in terms of overlapping symmetric transitions (Spink et al, 1982). The decrease in transition enthalpy with increasing peptide concentration is sometimes attributed to the withdrawing of lipid from the phase transition by association with the peptide (Akhrem et al, 1982). We have demonstrated that for this system, all of these characteristics are consistent with and perhaps consequences of the existence of a region of two-phase equilibrium.…”

Section: Discussionsupporting

confidence: 64%

“…We identify this AH with the integrated enthalpy of a DSC scan and see that, for small peptide concentration, a plot of AH/nx vs. X2 should display an intercept of AHX(T^) and a slope of AH2{TC) + (p1 -pg)/y. The slope of such plots has often been interpreted as reflecting the number of lipids prevented from participating in the transition due to their being perturbed by solute molecules (Akhrem et al, 1982;Ruppel et al, 1982;Gomez-Fernandez et al, 1980;Boggs et al, 1980;Boggs & Moscarello, 1978;Chapman et al, 1977). On the time scale of 2H NMR (10-6-10-3 s), however, there is little evidence for a distinct class of lipids ).…”

Section: Methodsmentioning

confidence: 99%

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Simultaneous modeling of phase and calorimetric behavior in an amphiphilic peptide phospholipid model membrane

Mr¹,

Jc²,

Jh³

1985

Biochemistry

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Differential scanning calorimetry (DSC) experiments have been performed on the amphiphilic peptide/1,2-bis(perdeuteriopalmitoyl)-sn-glycero-3-phosphocholine system for which partial phase diagrams have been measured by deuterium nuclear magnetic resonance. The solute concentration dependence of the transition enthalpy in such systems is often interpreted in terms of an annulus of lipid withdrawn, by the solvent, from participation in the transition while the bulk lipid melts with its fully enthalpy. This idea is equivalent to postulating ideal mixing between the lipid and the peptide/lipid complex, and there is little justification for such an assumption. Adaptation of regular solution theory to this system demonstrates that the peptide concentration dependence of the transition enthalpies can be incorporated into a thermodynamic model which reproduces the observed phase behavior fairly well without postulating that a complexing annulus of lipid around the peptide be withdrawn from participating in the chain-melting transition. The model parameters determined by simultaneous fitting of the phase behavior and transition enthalpies are used to simulate the DSC scan shapes. The asymmetry of the calorimetric scans for chi 2 less than or equal to 0.02 is reproduced by the model, but a broad component observed for higher concentration is not. In light of the results presented here, previous analyses of the calorimetric behavior of two-component systems in terms of symmetric transitions which do not account for the possible extent of a region of two-phase equilibrium must be questioned.

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Section: Discussionsupporting

confidence: 64%

Section: Methodsmentioning

confidence: 99%

Simultaneous modeling of phase and calorimetric behavior in an amphiphilic peptide phospholipid model membrane

Mr¹,

Jc²,

Jh³

1985

Biochemistry

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“…Ingelman-Sundberg et al [ll], for example, reported an increase in the reconstituted cytochrome-P450-LM,-catalysed 0-dealkylation of p-nitroanisole or ethoxycoumarin upon increasing the negative charge of the membrane. Furthermore, an increased thermal denaturation temperature of rat liver microsomal cytochrome P450 was observed in the presence of acy1,GroPIns [12]. These data from previous studies point to a special role of negatively charged, naturally occurring phospholipids in the cytochrome P450 system.…”

supporting

confidence: 65%

A Specific interaction between NADPH–cytochrome reductase and phosphatidylserine and phosphatidylinositol

Balvers

Boersma

Vervoort

et al. 1993

European Journal of Biochemistry

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In the present study the interaction of NADPH-cytochrome reductase with phospholipids was investigated using 31P-NMR, thin-layer chromatography combined with chemical analysis, fluorescence spectroscopy and kinetic studies with purified rat liver cytochrome P450 IIBl."P-NMR analysis demonstrates that the composition of the phospholipids that remain associated to NADPH -cytochrome reductase upon its purification is significantly different from the phospholipid composition of the microsomal membrane. Thin-layer chromatography followed by chemical analysis of the phospholipid composition demonstrates that the isolated NADPH -cytochrome reductase was enriched in L-a-l,2-diacyl-sn-glycero-3-phosphoserine (acy1,GroPSer) and L-a-l,2-diacyl-sn-glycero-3-phosphoinositol (acy1,GroPIns) compared to the microsomal membrane. The observed preference of NADPH -cytochrome reductase for acy1,GroPSer and acyl,GroPIns appeared not to be a result of the procedure for solubilisation and/or purification of the protein.The specific interaction of NADPH -cytochrome reductase with acy1,GroPSer and acy1,GroPIns was further investigated by comparison of the effect of acy1,GroPSer and acy1,GroPIns with that of acy1,GroPCho and acy1,GroPEtn on the 2-[3-(diphenylhexatrienyl)propanoyl]-l-hexadecanoyl-snglycero-3-phosphocholine-(DphPamGro~Cho)-dependent quenching of the tryptophan fluorescence of purified NADPH-cytochrome reductase. The results demonstrate that the addition of acy1,-GroPSer or acy1,GroPIns affects the DphPamGroPCho-dependent quenching of the tryptophan fluorescence in a manner significantly different from the addition of acy1,GroPCho or acy1,GroPEtn. The relatively larger DphPamGroPCho-induced quenching of the tryptophan fluorescence of NADPH-cytochrome reductase in the presence of acyl,GroPSer and acy1,GroPIns must result from a change in the conformation of NADPH-cytochrome reductase induced by the latter two lipids.Finally, the possible consequences of this special interaction of acyl,GroPSer and acy1,GroPIns with NADPH -cytochrome reductase on the kinetic characteristics of the cytochrome P450 system were studied using cytochrome-P450-IIB1 -dependent 0-dealkylation of pentoxyresorufin as the model reaction. These studies demonstrate that a 1 : 1 mixture of acy1,GroPCho and acy1,GroPSer results in a significantly higher apparent maximum rate (V) of 0-dealkylation than a 1 : 1 mixture of acy1,GroPCho and acy1,GroPEtn or acyl,GroPCho alone. This increase in the apparent V can be ascribed to an acy1,GroPSer-dependent improvement of the interaction of NADPH-cytochrome reductase with cytochrome P450. This improvement of the interaction of the proteins cannot, however, be exclusively ascribed to the negative charge of acyl,GroPSer, since the other negatively charged phospholipid investigated, namely acyl,GroPIns, resulted in a significant decrease in the apparent V In both cases the substrate apparent K,,, was not affected. This opposite effect of acy1,-GroPSer and acy1,GroPIns on the kinetics of the cytochrome P450 IIBl system m...

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“…This process may involve the fatty acids linked to the protein and would lead to PLA aggregation. Comparable results were reported by Silvius et al (1983) from ESR experiments on phospholipid-lipophilin systems and by Akhrem et al (1982) from DSC data on lipid-cytochrome P-450 mixtures.…”

Section: Discussionsupporting

confidence: 85%

Lipid solvation of the aqueous form of the myelin proteolipid apoprotein: evidence and characterization of two lipid populations by fluorescence polarization, differential calorimetry, and sucrose gradient centrifugation

Lavialle¹,

Grabielle-Madelmont²,

Petit³

et al. 1985

Biochemistry

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The interaction between dipalmitoylphosphatidylcholine (DPPC) and the aqueous form of the myelin proteolipid apoprotein (PLA) has been investigated. Lyophilization was found to be an efficient and nonperturbing method for membrane reconstitution. Mixtures of different lipid/protein ratios were analyzed by means of differential calorimetry, fluorescence polarization, and sucrose gradient centrifugation. The presence of two coexisting lipid populations, termed "bulk" and "interacting" lipids, was demonstrated by these three techniques. By differential calorimetry, 23 DPPC molecules per molecule of protein (30 kDa) were shown to be excluded from the lipid phase transition. By fluorescence polarization, we detected above the phase-transition temperature a large perturbation of the lipid acyl chain dynamics induced by the aqueous form of PLA. Increasing the protein content above 35% by weight within the recombinants caused drastic changes in both delta H values and the fluorescence anisotropy parameter, which could stem from protein aggregation.

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Thermotropic behaviour of phospholipid vesicles reconstituted with rat liver microsomal cytochrome P-450

Cited by 16 publications

References 38 publications

Simultaneous modeling of phase and calorimetric behavior in an amphiphilic peptide phospholipid model membrane

Simultaneous modeling of phase and calorimetric behavior in an amphiphilic peptide phospholipid model membrane

A Specific interaction between NADPH–cytochrome reductase and phosphatidylserine and phosphatidylinositol

Lipid solvation of the aqueous form of the myelin proteolipid apoprotein: evidence and characterization of two lipid populations by fluorescence polarization, differential calorimetry, and sucrose gradient centrifugation

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