Hydrophilic sulfhydryl reagent

A large and rigid hydrophilic sulfhydryl reagent, 4-acetamido-4 -[(iodoacetyl)amino] stilbene-2,2 -disulfonic acid (lASD) disodium salt. 

AMV RNase H is resistant to both hydrophobic and hydrophilic sulfhydryl reagents. NEM, a reagent specific to amino and SH groups, inactivates both polymerase and RNase H, but the RNase H activity is fourfold more resistant. The polymerase activity lost by DTNB or NEM modification can be partially (40-90%) recovered by incubation with 20 mM DTT (16). 

Modifiers in the flotation of sulphide minerals mainly include depressants and activators. A depressant is defined as a reagent which inhibits the adsorption of a collector on a given mineral or adsorbed on the mineral to make the siuface hydrophilic, and includes inorganic depressants such as lime, sodium cyanide, sulphin dioxide, zinc sulphate, sodium sulphide etc., and organic depressants such as sulfhydryl acetic acid, polyacrylamide polymers containing various functional groups etc. In this chapter, roles of depressants in the flotation sulphide minerals will be discussed and some new organic depressants will be introduced. 

Residues lining water-accessible binding sites will react with charged, hydrophilic, and sulfhydryl-specific reagents and with residues that face the interior of the protein or the lipid bilayer will not be accessible. 

Movements of small hydrophilic solutes across human and probably other biological membranes can be affected by certain sulfhydryl-reactive reagents such as PCMBS and by phloretin. In the case of human red-cell membrane, a system which has been thoroughly studied in this respect, either one of these two compounds inhibits drastically the movements of these molecules. As is evident in Table 5, the inhibitory effect on the permeability decreases as the value increases. Whereas the... 

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