Contribution of the active-site metal cation to the catalytic activity and to the conformational stability of phosphotriesterase: temperature- and pH-dependence.

Phosphotriesterase (PTE) detoxifies nerve agents and organophosphate pesticides. The two zinc cations of the PTE active centre can be substituted by other transition metal cations without loss of activity. Furthermore, metal-substituted PTEs display differences in catalytic properties.

The wild type bacterial Co(2+)/Co(2+)-phosphotriesterase shows a middle-range thermostability.

The phosphotriesterase (PTE) from Pseudomonas diminuta, a metalloenzyme that catalyses the hydrolysis of organophosphorus pesticides and nerve agents, has been described as a remarkably heat-stable protein [Grimsley et al., Biochemistry 36 (1997), 14366-14374]. Because substitution of the naturally occurring zinc ions by cobalt ions was found to enhance the enzyme catalytic activity, we investigated the thermal stability of the Co(2+)/Co(2+)-PTE.

Engineering of a monomeric and low-glycosylated form of human butyrylcholinesterase: expression, purification, characterization and crystallization.

Human butyrylcholinesterase (BChE; EC 3.1.1.

Thermal stability of acetylcholinesterase from Bungarus fasciatus venom as investigated by capillary electrophoresis.

Previous studies on the conformation of the monomeric acetylcholinesterase (AChE) from the krait (Bungarus fasciatus) venom showed that the protein possesses a large permanent dipole moment. These studies predicted that thermal irreversible denaturation must occur via partially unfolded states. The thermal stability of Bungarus AChE was determined using capillary electrophoresis (CE) with optimized conditions.

Enzymes hydrolyzing organophosphates as potential catalytic scavengers against organophosphate poisoning.

Enzymes hydrolyzing organophosphates could be used as catalytic scavengers for treatment of organophosphate poisoning and for decontamination. Two organophosphorus hydrolases (OPH) were selected: the Flavobacterium sp/Pseudomonas diminuta phosphotriesterase (PTE) and human paraoxonase (HuPON). Genes encoding these enzymes were cloned and functional recombinant enzymes expressed.