Chloroquine intercalates into DNA and protects cells against topoisomerase II (topo II) poisons such as etoposide by hindering the DNA cleavage reaction of this target enzyme. Chloroquine, in contrast to etoposide, is a weak base and therefore barely enters the cell when the extracellular fluid is acidic, as is the case in most solid tumors. Such a pH-dependent drug interaction could be useful ...

The MelB permease of Salmonella typhimurium (MelB-ST) catalyzes the coupled symport of melibiose and Na(+), Li(+), or H(+). In right-side-out membrane vesicles, melibiose efflux is inhibited by an inwardly directed gradient of Na(+) or Li(+) and stimulated by equimolar concentrations of internal and external Na(+) or Li(+). Melibiose exchange is faster than efflux in the presence of H(+) or Na(...

The ability of a number p-nitrophenylethyl alkyl, phenyl alkyl, chloroalkyl, and aminoalkyl phosphonates to inhibit the activated first component (C'1a) of guinea pig complement, and the antigen-induced release of histamine from sliced, perfused guinea pig lung has been compared. C'1a in its reactivity with these phosphonates is distinctly more similar to trypsin than to any of the other enzyme...

The application of the concept of backbone cyclization to linear substance P (SP) analogs is presented. We describe the synthesis, characterization, and biological activity of a series of backbone-to-amino-terminus cyclic analogs of the C-terminal hexapeptide of SP. These analogs were designed on the basis of NMR data and molecular modeling of the selective NK-1 analog WS-septide (Ac[Arg6,Pro9]...

Mannich bases are beta-amino ketone-carrying compounds that the end products of reaction. The reaction is essential in synthesis nitrogen-containing compounds. reaction, a nucleophilic addition forms carbon-carbon bonds, employed numerous natural products, drugs and other There several aminoalkyl chain bearing with high curative value, such as fluoxetine, atropine, ethacrynic acid, trihexypheni...