Thiols accumulation

The first compound of this class with inhibitory activity on the enzyme and on acid secretion was the 2-(pyridylmethyl)sulfinylbenzimidazole, timopra-zole, and the fust pump inhibitor used clinically was omeprazole, 2-[[3,5-dimethyl-4-methoxypyridin-2-yl] methylsulfinyl]-5-methoxy- lH-benzimidazole. Omeprazole is an acid-activated prodrug. Omeprazole and the other PPIs are accumulated in the acidic space of the parietal cell due to the pKa of the pyridine nitrogen and these are converted due to protonation of the benzimidazole nitrogen first to a thiol-reactive cationic sulfenic acid and then dehydrated to form the sulfenamide (Fig. 1). These thiophilic cations then bind to luminally... 

Ion-exchange reactions were used for the accumulation of europium(III) [158] and iron(III) [159] ions on the surface of GCE coated with Nafion , and chromium(VI) ions on the surface of GCE covered by a pyridine-functionalized sol-gel film [160], which were combined with the stripping SWV Furthermore, a cathodic stripping SWV was used for the determination of sulfide [161,162], thiols [163-166], selenium(lV) [167-170], halides [171-173] and arsenic [174] accumulated on the snrface of mercury electrode. 

Thiol-functionalized dendrimers have also been used as surface stabilizers to obtain dendrimer stabilized Au NPs (DSNs) of very small size (1.5-2.1 nm). The study shows that dendrimer molecules are highly flexible and can undergo a conformational change to accumulate thiol terminal groups on one side of the molecule interacting with the nanoparticle surface [124] (Scheme 3.19). 

The clinical usefulness of cis-Pt is often limited by the development of resistance. The development of resistance to cis-Pt has been explained by several factors, including reduced drug accumulation, increased DNA repair processes, and an increase in the amount of inactivation proteins. In most cis-Pt-resistant tumors probably a combination of such factors plays a role. In this section, only an increase in cellular thiols in relation to resistance will be discussed. Such inactivation processes have already been discussed (Section IV,B), but attention will be directed now to the mechanism of resistance. These mechanisms are probably also of importance for the inactivation of cis-Pt in nonre-sistant tumors, though to a lesser extent. 

Schaffer, M.A. Fischer, R.L. (1988). Analysis of mRNAs that accumulate in response to low temperature identifies a thiol protease gene in tomato. Plant Physiology 87, 431-6. 

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