The acetohydroxamic acid (AHA), a potent inhibitor of urease, inhibits soybean urease competitively and reversibly. The I 50 and K i value for AHA were 900 M and 0.053 mM, respectively at pH 7.0, 37 °C. The variation in pH over the pH 6 9 affected K i and therefore binding of AHA in the active site. The affinity of AHA for the active site decreases with lowering of pH (below the pK a value of ...

The RGSZ2 gene, a regulator of G protein signaling, has been implicated in cognition, Alzheimer's disease, panic disorder, schizophrenia and several human cancers. This 210 amino acid protein is a GTPase accelerating protein (GAP) on Gαi/o/z subunits, binds to the N terminal of neural nitric oxide synthase (nNOS) negatively regulating the production of nitric oxide, and binds to the histidine t...

[14C]Aflatoxin B1 (AFB1) was isolated from cultures of Aspergillus parasiticus grown on [1-14C]sodium acetate. Covalent binding of AFB1 to liver DNA of rat and mouse was determined 6-8 h after oral administration. The effectiveness of covalent binding, expressed as DNA binding per dose in the units of a 'Covalent Binding Index' (CBI), (micromol aflatoxin/mol DNA nucleotides)/(mmol aflatoxin/kg ...

Thiosemicarbazones (TSCs) possess significant antimalarial properties believed to be linked to the inhibition of major cysteine proteases, such as falcipain-2, in Plasmodium falciparum. However, the binding modes of TSCs to the active site of these enzymes are not clear. As a result of this, the nature of the bonding interactions between the active site of falcipain-2 and different derivatives ...

A new method has been developed for measuring the total covalent binding of metabolically activated compounds to cellular macromolecules. This method employs equilibrium dialysis, in the presence of the detergent sodium dodecyl sulfate (SDS), to remove unbound radiolabeled compound and its metabolites from cellular macromolecules. [14C] Bromobenzene (80 microM), [14C]aflatoxin B1 (5 microM) or...

I Ilipiiiiiiiin acétate(9-OH-NME; Celiptium) is an antineoplastic agent currently used in the treatment of metastatic breast cancer and is known to intercalate into DNA. Previous studies have demonstrated that this molecule can be oxidized, yielding a reactive electrophilic form, which is able to bind covalently to a nucleophilic biological molecule. In this work, we evidenced a covalent bindi...

Elliptinium acetate (9-OH-NME; Celiptium) is an antineoplastic agent currently used in the treatment of metastatic breast cancer and is known to intercalate into DNA. Previous studies have demonstrated that this molecule can be oxidized, yielding a reactive electrophilic form, which is able to bind covalently to a nucleophilic biological molecule. In this work, we evidenced a covalent binding o...

The human gastric pathogen Helicobacter pylori is extremely well adapted to the highly acidic conditions encountered in the stomach. The pronounced acid resistance of H. pylori relies mainly on the ammonia-producing enzyme urease; however, urease-independent mechanisms are likely to contribute to acid adaptation. Acid-responsive gene regulation is mediated at least in part by the ArsRS two-comp...