Detail of "81490-05-3"

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Physical chemical properties of some mixtures of lipids and their potential for use as exogenous pulmonary surfactants

Physical chemical properties of some mixtures of lipids and their potential for use as exogenous pulmonary surfactants. Keough, K. M. W. (Dep. Biochem. Discip. Pediatr., Mem. Univ. Newfoundland, St. John's, NF A1B 3X9, Can.). Prog. Respir. Res., 18(Curr. Concepts Surfactant Res.), 257-62 (English) 1984. CODEN: PGRRB6. ISSN: 0079-6751. DOCUMENT TYPE: Journal CA Section: 1 (Pharmacology) Various lipid mixts. were tested as surface-active materials for their ability to quickly achieve a low surface tension at air-water interfaces and to be stable in that state. Using a 3-component system contg. dipalmitoylphoshatidylcholine, a fluidizing lipid, and a potential bilayer destabilizing lipid, a no. of mixts. were found which were able to reach a surface tension ￡5mN/m within 2 min of pulsing when tested on a pulsating bubble surfactometer. Tests to see what min. no. of components of natural surface-active materials may allow for an adequate synthetic surface-active material were done. The cholesterol [13699-47-3]-dipalmitoylphoshatidylcholine [2644-64-6]-oleoylpalmitoylphosphatidylcholine [17118-56-8]-1-palmitoyl-2-oleoylphosphatidylglycerol [81490-05-3] mixt. had collapse plateau ratios 50% or more of those of whole surface active material lipids. The mixt. was dependent in Ca2+ for the performance shown, but this mixt. also had given dispersions which did not reach low opening pressures very rapidly. These mixts. could be modified with fatty acids and triglycerides, so that rapid monolayer formation was possible, but these modified materials have shown relatively high opening pressures at max-bubble size. The use of these mixts. as exogenous pulmonary surfactants is discussed.

Bilayer interactions of indolicidin, a small antimicrobial peptide rich in tryptophan, proline, and basic amino acids

Bilayer interactions of indolicidin, a small antimicrobial peptide rich in tryptophan, proline, and basic amino acids. Ladokhin, Alexey S.; Selsted, Michael E.; White, Stephen H. ( Department of Physiology and Biophysics, University of California, Irvine, CA 92697-4560, USA). Biophysical Journal, 72(2, Pt. 1), 794-805 (English) 1997 Biophysical Society. CODEN: BIOJAU. ISSN: 0006-3495. DOCUMENT TYPE: Journal CA Section: 6 (General Biochemistry) Section cross-reference(s): 9 Tryptophan, proline, and basic amino acids have all been implicated as being important in the assembly and structure of membrane proteins. Indolicidin, an antimicrobial 13-residue peptide-amide isolated from the cytoplasmic granules of bovine neutrophils, is highly enriched in these amino acids: five tryptophans, three prolines, three basic residues, and no acidic residues. Consistent with the likely importance of these amino acids in membrane protein assembly, indolicidin is known to be highly membrane-active and is believed to act by disruption of cell membranes.Some commonly used reagents like 81490-05-3 and 140896-21-5 are used in this experiment. We have, therefore, examd. the interactions of native indolicidin with large unilamellar vesicles (LUV) formed from palmitoyloleoylphosphatidylcholine (POPC), and palmitoyloleoylphosphatidylglycerol (POPG), in order to use it as a model system for studying membrane protein insertion and for evaluating the relative contributions of hydrophobic and electrostatic forces in peptide-bilayer interactions. Equil. dialysis measurements indicate that indolicidin binds strongly, but reversibly, to both neutral POPC and anionic POPG vesicles with free energies of transfer of -8.8 ± 0.2 and -11.5 ± 0.4 kcal/mol, resp. The extremely strong partitioning into POPG vesicles necessitated the development of a new equil. dialysis method that is described in detail. Tryptophan fluorescence measurements show that indolicidin is located in the bilayer interface and that indole fluorescence is affected by the type of lipid used to form the LUVs. CD measurements reveal unordered conformations in aq. and bulk org. solns. and a somewhat more ordered, but not a-helical, conformation in SDS micelles and lipid bilayers. Fluorescence requenching measurements (Ladokhin et al. 1995, Biophys. J. -1971) on vesicles loaded with the fluorophore/quencher pair 8-aminonaphthalene-1,3,6 trisulfonic acid (ANTS)/p-xylene-bis-pyridinium bromide (DPX), show that indolicidin induces membrane permeabilization. For anionic POPG, leakage is graded with a high preference for the release of cationic DPX over anionic ANTS. For neutral POPC vesicles no such preference is obsd. Leakage induction is more effective with POPG vesicles than with POPC vesicles, as judged by three quant. measures that are developed in the Appendix. .