vist and davis 2H NMR cholesterol phase biochemistry 1990

vist and davis 2H NMR cholesterol phase biochemistry 1990 -...

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
Biochemistry 1990, 29, 45 1-464 45 1 Guggenheim, S., & Flavin, M. (1969b) J. Biol. Chem. 244, & Flavin, M. (1971) J. Biol. Chem. 246, Holbrook, E. ( 1984) Doctoral Dissertation, Duke University. Holbrook, E. L., Greene, R. C., & Krueger, J. H. (1990) (preceding paper in this issue). Jencks, W. P. (1 969) Catalysis in Chemistry and Enzymology, pp 133-146, McGraw-Hill, New York. Johnston, M., Marcotte, P., Donovan, J., & Walsh, C. (1979a) 18, 1729-1738. Johnston, M., Jankowski, D., Marcotte, P., Tanaka, H., Esaki, N., Soda, K., & Walsh, C. (1979b) Biochemistry 18, Johnston, M., Raines, R., Chang, M., Esaki, N., Soda, K., & Walsh, C. (1981) Biochemistry 20, 4325-4333. Kallen, R. G., Korpela, T., Martell, A. E., Matsushima, Y., Metzler, C. M., Metzler, D. E., Morozov, Y. V., Ralston, I. M., Savin, F. A., Torchinsky, Y. M., & Ueno, H. (1985) The Transaminases, pp 37-105, Wiley, New York. 621 7-6227. 3562-3568. 4690-470 1. Kaplan, M. M., & Flavin, M. (1966) J. Biol. Chem. 241, Karube, Y., & Matsushima, Y. (1977) J. Am. Chem. SOC. 9, Koerber, S. C., MacGibbon, A. K. H., Dietrich, H., Zeppe- quaer, M., & Dunn, M. F. (1983) Biochemistry 22, Metzler, D. E., Harris, C. M., Johnson, R. J., Siano, D. B., & Thomson, J. A. (1973) Biochemistry 12, 5377-5392. Posner, B. I., & Flavin, M. (1972a) J. Biol. Chem. 247, Posner, B. I., & Flavin, M. (1972b) Tanizawa, K., & Soda, K. (1979) J. Biochem. 86, 1199-1209. Tate, S. S., & Meister, A. (1974) Adv. Enzymol. Relat. Areas Walsh, C. (1979) Enzymatic Reaction Mechanisms, pp Washtien, W., Cooper, A. J. L., & Abeles, R. H. (1977) 4463-447. 1356-1358. 3424-343 1. 6402-64 1 1. 6412-6419. Mol. Biol. 35, 503-543. 777-827, Freeman, San Francisco. Biochemistry 16, 460-463. Phase Equilibria of Cholesterol/Dipalmitoylphosphatidylcholine Mixtures: 2H Nuclear Magnetic Resonance and Differential Scanning Calorimetry+ Margus R. Vist* and James H. Davis* Department of Physics, University of Guelph, Guelph, Ontario, Canada NlG 2 W1 Received May 11, 1989; Revised Manuscript Received August 24, 1989 ABSTRACT: Deuterium nuclear magnetic resonance spectroscopy and differential scanning calorimetry are used to map the phase boundaries of mixtures of cholesterol and chain-perdeuteriated 1,2-dipalmitoyl-sn- glycero-3-phosphocholine at concentrations from 0 to 25 mol % cholesterol. Three distinct phases can be identified: the La or liquid-crystalline phase, the gel phase, and a high cholesterol concentration phase, which we call the 0 phase. The liquid-crystalline phase is characterized by highly flexible phospholipid chains with rapid axially symmetric reorientation; the gel phase has much more rigid lipid chains, and the motions are no longer axially symmetric on the 2H NMR time scale; the 0 phase is characterized by highly ordered (rigid) chains and rapid axially symmetric reorientation. In addition, we identify three regions of two-phase coexistence. The first of these is a narrow La/gel-phase coexistence region lying between 0 and about 6 mol % cholesterol at temperatures just below the chain-melting transition of the pure phospho- lipid/water dispersions, at 37.75 OC. The dramatic changes in the *H NMR line shape which occur on passing through the phase transition are used to map out the boundaries of this narrow two-phase region. The boundaries of the second two-phase region are determined by 2H NMR difference spectroscopy, one boundary lying near 7.5 mol 5% cholesterol and running from 37 down to at least 30 OC; the other boundary lies near 22 mol cholesterol and covers the same temperature range. Within this region, the gel and
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 09/19/2011 for the course CHM 6304 taught by Professor Richards during the Fall '08 term at University of Florida.

Page1 / 14

vist and davis 2H NMR cholesterol phase biochemistry 1990 -...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online