کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
9757658 | 1496382 | 2005 | 12 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Phospholipid containing mixed micelles
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کلمات کلیدی
Dodecyl trimethylammonium bromideTime-resolved fluorescence quenching - خنثیسازی فلورسنت حل شده با زمانElectron spin resonance - رزونانس اسپین الکترونsodium dodecyl sulfate - سدیم دودسیل سولفاتAggregation number - شماره جمعآوریPhospholipids - فسفولیپیدMixed micelles - میسل های مخلوطMicroviscosity - میکروویو بودنHydration - هیدراتاسیون
موضوعات مرتبط
مهندسی و علوم پایه
شیمی
شیمی (عمومی)
پیش نمایش صفحه اول مقاله
چکیده انگلیسی
Mixed micelles of l,2-diheptanoyl-sn-grycero-3-phosphocholine (DHPC) with ionic detergents were prepared to develop well characterized substrates for the study of lipolytic enzymes. The aggregates that formed on mixing DHPC with the anionic surfactant sodium dodecyl sulfate (SDS) and with the positively charged dodecyl trimethylammonium bromide (DTAB) were investigated using time-resolved fluorescence quenching (TRFQ) to determine the aggregation numbers and bimolecular collision rates, and electron spin resonance (ESR) to measure the hydration index and microviscosity of the micelles at the micelle-water interface. Mixed micelles between the phospholipid and each of the detergents formed in all compositions, yielding interfaces with varying charge, hydration, and microviscosity. Both series of micelles were found to be globular up to 0.7Â mole fraction of DHPC, while the aggregation numbers varied within the same concentration range of the components less than 15%. Addition of the zwitterionic phospholipid component increased the degree of counterion dissociation as measured by the quenching of the fluorescence of pyrene by the bromide ions bound to DHPC/DTAB micelles, showing that at 0.6Â mole fraction of DHPC 80% of the bromide ions are dissociated from the micelles. The interface water concentration decreased significantly on addition of DHPC to each detergent. For combined phospholipid and detergent concentration of 50Â mM the interface water concentration decreased, as measured by ESR of the spin-probes, from 38.5Â M/L of interface volume in SDS alone to 9Â M/L when the phospholipid was present at 0.7Â mole fraction. Similar addition of DHPC to DTAB decreased the interfacial water concentration from 27Â M/L to 11Â M/L. Determination of the physicochemical parameters of the phospholipid containing mixed micelles here presented are likely to provide important insight into the design of assay systems for kinetic studies of phospholipid metabolizing enzymes.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Chemistry and Physics of Lipids - Volume 135, Issue 1, May 2005, Pages 93-104
Journal: Chemistry and Physics of Lipids - Volume 135, Issue 1, May 2005, Pages 93-104
نویسندگان
Radha Ranganathan, Carolina Vautier-Giongo, Mandeep Singh Bakshi, Barney L. Bales, Joseph Hajdu,