A-Galactocerebrosides

Example 13.4. The result of a typical X-ray measurement is shown in Fig. 13.10 for a galactocerebroside [605], The plot on the left side shows the normalized reflected X-ray beam intensity versus the incident angle a for two different film pressures. The pressure-area isotherm is shown in the inset, together with the points of measurement a and b. On the right side are the extracted electron density profiles normal to the film surface taken at the same film pressures. At 0 A we find the monolayer surface (top of the alkyl chains), a depth of -40 A corresponds to pure water. In between is the film. The measurement is so sensitive that we even find two different electron densities within the monolayer. This is illustrated by the dashed boxes denoted by film 1 and film 2 (shown for curve b only) which represents the simplified electron density distribution in the so-called two-box model. A box is defined as a part in the film of a certain thickness where the electron density is constant. In the two-box model the film is divided into two layers. Film 1 represents the hydrocarbon tails, film 2 corresponds to the mean electron density of the head groups. 

D. CDP-choline reacts with a diacylglycerol to form phosphatidylcholine. UDP-galactose reacts with ceramide to form a galactocerebroside. Cytosine nucleotides are not required for... 

Figure 14-12. Structure of galactosylcer-amide (galactocerebroside, R = H), and sul-fogalactosylceramide (a sulfatide, R = S04 ).

Structure of a neutral glycosphingolipid, galactocerebroside (R is a fatty acid hydrocarbon chain). 

Fig. 2. Structures of (a) the sphingolipids sphingomyelin and galactocerebroside (b) cholesterol. R1 represents the hydrocarbon chain of fatty acids.

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