Inhibition of an organophosphate-detoxifying bacterial phosphotriesterase by albumin and plasma thiol components
| Autor: | Anja Köhler, Arne Skerra, Laura Job, Franz Worek |
|---|---|
| Rok vydání: | 2021 |
| Předmět: |
Serum albumin
chemistry.chemical_element Zinc Toxicology chemistry.chemical_compound Organophosphate Poisoning Organophosphorus Compounds Bacterial Proteins In vivo Albumins Sulfhydryl Compounds Enzyme Inhibitors Cells Cultured chemistry.chemical_classification biology Organophosphate Albumin Active site General Medicine Caulobacteraceae Enzyme Phosphoric Triester Hydrolases Biochemistry chemistry Models Animal Thiol biology.protein |
| Zdroj: | Toxicology letters. 350 |
| ISSN: | 1879-3169 |
| Popis: | The phosphotriesterase of the bacterium Brevundimonas diminuta (BdPTE) is a naturally occurring enzyme that catalyzes the hydrolysis of organophosphate (OP) nerve agents as well as pesticides and offers a potential treatment of corresponding intoxications. While BdPTE mutants with improved catalytic efficiencies against several OPs have been described, unexpectedly, less efficient breakdown of an OP was observed upon application in an animal model compared with in vitro measurements. Here, we describe detailed inhibition studies with the high-activity BdPTE mutant 10-2C3(C59M/C227A) by human plasma components, indicating that this enzyme is inhibited by serum albumin. The inhibitory activity is mediated by depletion of crucial zinc ions from the BdPTE active site, either via the known high-affinity zinc binding site of albumin or via chemical complex formation with its free thiol side chain at position Cys34. Albumin pre-charged with zinc ions or carrying a chemically blocked Cys34 side chain showed significantly reduced inhibitory activity; in fact, the combination of both measures completely abolished BdPTE inhibition. Consequently, the available zinc ion concentration in blood plays an important role for BdPTE activity in vivo and should be taken into account for therapeutic development and application of a catalytic OP scavenger. |
| Databáze: | OpenAIRE |
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