Deuterated glycerol

Two isomers of chirally deuterated glycerol have been synthesized from a common boronic ester intermediate 1 (synthesis Section I.I.2.1.3.I.)71. (15,25)-Glycerol-l-fi results if the carbon to which the label is attached is derived from dibromomethane and incorporated into an a-bromo boronic ester intermediate 2, which is then reduced with potassium triisopropoxyborodeuteride to the (1 / ,2/ )-l-deutero boronic ester 3. The synthesis of (lS,25)-glycerol-l- / is completed efficiently by dcboronation with hydrogen peroxide and debenzylation with hydrogen over palladium. 

To investigate these ideas, a simple experiment based on the deposition on the metallic surface of a thin layer of deuterated glycerol was performed. Under this condition, when the analysis of the PHGGGWGQPHGGGWGQ peptide was performed by SACI, the signal of the [M + D+] ion at m/z 1573 was observed to dominate (Fig. 1.19). This evidence is good for the participation of the chemicals present on the surface in the ionization phenomena occurring in SACI. 

Figure 1.19. The SACI spectrum of the peptide PHGGGWGQPHGGGWGQ obtained by the pretreatment of the metallic surface with deuterated glycerol.

One of the major problems facing distance determination by pulsed EPR on spin labeled membrane proteins is the short relaxation time (generally around 1 ps). Solvent deuteration is routinely used (10-20 vol% deuterated glycerol as cryopro-tectant for membrane-embedded or detergent-solubilized samples, or deuterated buffer) to slow down the nitroxide relaxation, thus extending the range of distance measurement and sensitivity. However, the problems coimected to the too fast relaxation time called for a systematic analysis of all factors modifying the... 

To further our understanding of interaction between the heme isopropionate side chains and the solvent, the kinetic energy relaxation of the excited heme in Mb was simulated in various solvents, including normal water (HjO), heavy water (D2O), normal glycerol (Gly-hg), deuterated glycerol (Gly-dg), and a nonpolar solvent. Two forms of the heme, one native and one lacking acidic side chains, were employed in the simulations which, together with different solvents, provided various interaction feature between the heme and the environment [55]. 

Other alternatives are the lyso-phosphatidylglycerol derivatives in which one of the fatty acid chains coupled to glycerol have been removed. Unfortunately, the phosphatidyl lipids are not available in fully deuterated form, and hence certain regions of the proton spectra will be covered by the glycerol protons. 

S)-Glycerol-l-rf results if the order of introduction of hydrogen and deuterium on C-1 is reversed. Thus, the common intermediate 1 with the lithio derivative of deuterated dibromomethane forms the deuterated broino boronic ester 4. It is not necessary to use more than one molar equivalent of dibromomethane-t/2. With an unlabeled hydride source such as lithium tricthylborohydride, 4 yields the (lS, 2/ )-l-deutero boronic ester 5, which is deboronated and deprotected to (l/f,25,)-giycerol-l-d . Labeled glycerol has been made in batches of 0.3 - 0.8 g by this route. 

Deuterated phospholipids l,2-dimyristoyl-.v -glycero-3-phosphocholinc (DMPC-c/s4), 1,2-dimyristoyl-.s -glyccro-3- phospho-rac-( 1 -glycerol) (DMPG-J54), and L2-dihexanoyl-.sy -glyccro-3-phosphocholinc (DHPC-c/22) as well as the undeuter-ated DMPC, DMPG, and DHPC Avanti Polar Lipids, Alabaster (AL, USA)... 

The pearl necklace model for the BSA-dodecylsulphate complexes is very different from the model used to interpret the neutron diffraction data for the complexes formed between the deuterated bifunctional enzyme N-5 -phosphoribosylanthranilate/indole-3-glycerol-phosphate... 

Deuteration levels are dependent on the protonated carbon source in use for reason of the exact relationship that the carbon source has to the metabolic pathways in operation. Deuteration levels are best assayed by NMR methods [1-3], both in vivo and in vitro, and checked in the neutron experiment by a matchpoint determination [61]. For example, Escherichia coli grown in 100% H20 with glycerol will lead to 60% deuteration of RNA and 90% deuteration of protein. Of great practicality is the use of RNA and proteins which are deuterated to match out in exactly 100% H20. This can be done with E. coli grown on a glucose source in 76% H20 for RNA and 84% H20 for proteins. Ribosomes prepared from these are... 

Fig. 5.5 Depth concentration profiles of deuterated a-w-end functional dPS-COOH afler annealing in glycerol at 150 °C for 0 min (open circles), 10 min (filled squares) and 30 min (open triangles). Reproduced with permission from [42]...

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