The purpose of this study is to summarize the current knowledge of the enzymes which are involved in the hydrolysis of cyanide, i.e., cyanide hydratases (CHTs; EC 4.2.1.66) and cyanide dihydratases (CynD; EC 3.5.5.1). CHTs are probably exclusively produced by filamentous fungi and widely occur in these organisms; in contrast, CynDs were only found in a few bacterial genera. CHTs differ from CynDs in their reaction products (formamide vs. formic acid and ammonia, respectively). Several CHTs were also found to transform nitriles but with lower relative activities compared to HCN. Mutants of CynDs and CHTs were constructed to study the structure-activity relationships in these enzymes or to improve their catalytic properties. The effect of the C-terminal part of the protein on the enzyme activity was determined by constructing the corresponding deletion mutants. CynDs are less active at alkaline pH than CHTs. To improve its bioremediation potential, CynD from Bacillus pumilus was engineered by directed evolution combined with site-directed mutagenesis, and its operation at pH 10 was thus enabled. Some of the enzymes have been tested for their potential to eliminate cyanide from cyanide-containing wastewaters. CynDs were also used to construct cyanide biosensors.
- MeSH
- Bacteria enzymologie MeSH
- biosenzitivní techniky * MeSH
- biotransformace MeSH
- dehydratasy chemie genetika metabolismus MeSH
- houby enzymologie MeSH
- hydrolasy chemie genetika metabolismus MeSH
- hydrolýza MeSH
- koncentrace vodíkových iontů MeSH
- kyanidy analýza metabolismus MeSH
- látky znečišťující životní prostředí analýza metabolismus MeSH
- mutační analýza DNA MeSH
- mutantní proteiny genetika metabolismus MeSH
- proteinové inženýrství MeSH
- stabilita enzymů MeSH
- vztahy mezi strukturou a aktivitou MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- přehledy MeSH
This paper describes a method for the determination of cyanide using in-capillary enzymatic reaction with rhodanese. Poorly absorbing cyanide is in rhodanese reaction transformed into highly absorbing thiocyanate that is further separated by capillary electrophoresis (CE) and determined spectrophotometrically at 200 nm. Cyanide is thus estimated indirectly from the result of thiocyanate quantification and moreover, it can be easily determined with sufficient sensitivity by means of CE apparatus equipped with common UV detector. The linear detection range for concentration versus peak area for the assay is from 15 to 500 microM (correlation coefficient 0.997) with a detection limit of 3 microM and a limit of quantitation 9 microM. The inter-day reproducibility of the peak area was below 3.2% and the inter-day reproducibility of the migration time below 0.1%. The method is relatively rapid, simple and can be easily automated. Moreover, only limited amount of the sample is required.
- MeSH
- hypotonické roztoky aplikace a dávkování terapeutické užití MeSH
- kyanidy analýza otrava MeSH
- lidé středního věku MeSH
- lidé MeSH
- nitroprusid aplikace a dávkování terapeutické užití MeSH
- thiokyanatany analýza otrava MeSH
- Check Tag
- lidé středního věku MeSH
- lidé MeSH
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- Publikační typ
- kazuistiky MeSH
- MeSH
- fekální inkontinence chemicky indukované veterinární MeSH
- játra chemie MeSH
- konjunktivitida chemicky indukované veterinární MeSH
- kyanidy analýza MeSH
- nemoci ovcí chemicky indukované MeSH
- neuromuskulární nemoci chemicky indukované veterinární MeSH
- pyrethriny otrava MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
