Lactose radioactive

Charley and Saltman studied the migration of radioactive Ca2ffi in the presence and absence of lactose in aqueous solution at pH 7.0. The solutions were buffered with sodium hydrogen carbonate. The inability of calcium to migrate in the presence of lactose indicated that Ca2ffi had reacted with the sugar to form a soluble, uncharged complex. 

Purification of the membrane-bound lactose carrier protein is a very different problem from the purification of the soluble OMP synthase. Both the approach to purification and the assays for the protein during purification are quite novel. The assay involves reconstituting a transport system with membranes that are free of lactose carrier protein, then adding the partially purified carrier protein and radioactively labeled lactose. The activity in this assay system is proportional to the transport of radioactive lactose across the membrane in the cell-free reconstituted system. 

Figure 4. Binding of biotinylated Alio A lectin to aryl lactose derivatised PS surfaces. Derivatised surfaces were incubated with Alio A lectin and then extensively washed to remove physisorbed lectins. [ S] streptavidin was incubated and the surfaces were again rinsed to remove excess streptavidin. (A) Pristine PS, (B) MAD-Gal desposited and washed, and (C) MAD-Gal light actived and washed. The radioactivity was measured by scintillation counting after Chevolot.5...

It was also demonstrated that the radioactivity on the surface increased with incubation time. When incubated without the enzyme, radioactivity was similar to the background level. These results illustrate that the enzyme was able to recognize lactose on PS surface as a substrate for the transfer of sialic acid and to catalyze this transfer [105],... 

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