Determination of propagation and termination rate constants by using an extension to the rotating-sector method: Application to PLPC and DLPC bilayers
✍ Scribed by F. Antunes; R. E. Pinto; L. R. C. Barclay; M. R. Vinqvist
- Publisher
- John Wiley and Sons
- Year
- 1998
- Tongue
- English
- Weight
- 241 KB
- Volume
- 30
- Category
- Article
- ISSN
- 0538-8066
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✦ Synopsis
An extension to the rotating-sector method, which is usually applied to determine propagation and termination rate constants, is presented. The analytical treatment developed accounts for the simultaneous presence of a thermal initiation and of a first-order termination process. The applicability of the rotating-sector method is thus extended to situations where the rate in dark is higher than 5% of the rate in the presence of light, and more accurate estimates of the rate constants are obtained than before for any values of the "dark" rate. A previously published experiment on the application of the rotating-sector method to the autoxidation of styrene was reanalyzed. The estimates obtained for the propagation and the termination rate constants were 11% and 19% higher than the previous estimates, respectively. Finally, the improved rotating-sector method was also applied to the experimental determination of propagation and termination rate constants for both 1-palmitoyl-2-(k )
( 2 ϫ k ) p t linoleoyl-sn-glycero-3-phosphocholine (PLPC) and 1,2-dilinoleoyl-sn-glycero-3-phosphocholine (DLPC) liposomes. The following results were obtained at 37ЊC: for PLPC k ϭ p and for DLPC Ϫ1 Ϫ1 5 Ϫ1 Ϫ1
16.6 M s , 2 ϫ k ϭ 1.27 ϫ 10 M s ; k (intermolecular) ϭ (13.3-13.9)