With the novel possibilities for detecting molecules of interest with extreme sensitivity also comes the risk of encountering hitherto negligible sources of error. In life science, such sources of error might be the broad variety of additives such as dithiothreitol (DTT) used to preserve enzyme stability during in vitro reactions. Using two different assays that can sense strand interruptions i...

Incubation of purified phosphoenolpyruvate carboxylase from Zea mays L. leaves with dithiothreitol resulted in an almost 2-fold increase in the enzymic activity. The activated enzyme showed the same affinity for its substrates and the same sensitivity with respect to malate and oxalacetate inhibition. The activation induced by dithiothreitol was reversed by diamide, an oxidant of vicinal dithio...

sequential processes that occur during nuclear reconstitution : first each individual chromosome becomes surrounded by a double membrane with pores characteristic of a nuclear membrane (Harris, 1962; Longo, 1972), then the membranebounded chromosome vesicles (karyomeres) fuse Sea Urchins to form a single membrane-bounded nucleus containing the full complement of chromosomes (Wilson, 1925 ; Mazi...

Purified ribulose-1,5-bisphosphate carboxylase/oxygenase in 50% saturated (NH(4))(2)SO(4) was stable when frozen as small beads in liquid nitrogen and stored at -80 C. When stored as a slurry at 4 C most of the activity was lost within four weeks. This loss was due not only to enzyme polymerization. Activity in old preparations purified from spinach leaves, but not tobacco or tomato leaves, can...

The glutaminase activity of glutamine-dependent carbamyl phosphate synthetase (Escherichia coli) and that of the separated light subunit of this enzyme, as well as the glutaminedependent synthetase activity catalyzed by the native enzyme, are inactivated by incubation in air with relatively low concentrations (0.025 to 1 mM) of dithiothreitol; oxidized dithiothreitol does not inhibit. Other mer...

The transition from the closed to open state greatly alters the intra- and inter-subunit interactions of the P2X receptor (P2XR). The interactions that occur in the transmembrane domain of the P2X2R remain unclear. We used substituted cysteine mutagenesis disulfide mapping to identify pairs of residues that are in close proximity within the transmembrane domain of rP2X2R and compared our result...