Hydrogen penetration probe

Man, P, Montagner, C., Vitrac, H., et al. (2011) Accessibility changes within diphtheria toxin T domain upon membrane penetration probed by hydrogen exchange tmd mass spectrometry. Journal of Molecular Biology, 414 (1), 123-134. 

Fig. 12.13 An dectrochemical patch probe for the meesuretnent of the hydrogen penetration rate through a process vessel or pipe. Courtesy Petrolite Corp.)...

The ability of a CD to form inclusion complexes in aqueous solution results from its cavity, the interior of which is less polar than water and hydrophobic. The apparent polarity of the CD cavity seems to depend on the probe used. Some studies have suggested a similarity to dioxane (Bender and Komiyama, 1978 Hamai, 1982), while others favour ethanol (Cox et al., 1984 Heredia et al., 1985). No doubt the particular observations are affected by the presence or absence of specific interactions, such as hydrogen bonding, between the guest and the CD host, as well as by the depth of penetration of the guest/probe. Decarboxylation studies, to be discussed more fully later, suggest an environment like 50% aqueous 2-propanol (Straub and Bender, 1972a,b). 

Normal Micelles - Solubilizate Probes. The addition of a probe molecule, usually bearing a C=0 group, to a micelle has been used to asses die solubilization site of the probe (67) and to infer the extent of penetration of water into micelles (68,69). The basis of such studies is the well known decrease in the 0=0 band frequency upon hydrogen bond formation (70 -73). Two important concepts must be addressed, however, when using probes in studies of micelles the solubilization site of the probe (micelle core or palisade layer) and the possibility of probe-induced changes in the micelle. 

I). We interpret the cholesterol-induced increase in hydrogen bonding below Tc (Figure 3A) as being due to an opening of the bilayer which allows more solvent to penetrate. Similar conclusions were reached from studies of doxyl stearic acid spin probes in frozen lipid vesicles... 

Moisture is a well-known plasticizer for macromolecules (14). Specifically, water penetrates into an epoxy network and can lower the glass temperature of the resin (15). In this report, moisture has for the first time been utilized as a probe to characterize denslfIcatlon process during epoxy aging. Also, using the same rationale, heavy water diffused Into the epoxy resin Is used to study the Interactions of moisture with the aging polymer by hydrogen-2 (deuterium) NMR spectroscopy. 

---