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.

• Klíčová slova
• Cyanide biosensors, Cyanide dihydratase, Cyanide hydratase, Enzyme production, Structure-activity relationships, Wastewater bioremediation,
• 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
• Názvy látek
• cyanide dihydratase MeSH Prohlížeč
• cyanide hydratase MeSH Prohlížeč
• dehydratasy MeSH
• hydrolasy MeSH
• kyanidy MeSH
• látky znečišťující životní prostředí MeSH
• mutantní proteiny MeSH

An original setup for analysis of glycated haemoglobin (HbA1c) in blood is reported. The construction employed a combination of the piezoelectric biosensor for glycated haemoglobin and the flow-through photometric sensor for total haemoglobin (Hb). The modification of gold electrodes with 3-aminophenylboronic acid (APBA) as a specific ligand was studied; the chemisorbed conjugate of APBA with a long-chain thiocompound provided the best affinity for HbA1c. The effect of various operating parameters, such as flow rate and instrumental setup, was optimised. The total haemoglobin content was analysed as absorbance of the haemoglobin-cyanide derivative at 540 nm. Only one standard (calibrator) diluted in various ratio was necessary for calibration and 1 microl of blood was sufficient for analysis. The full range of HbA1c content (4-15%) in blood can be analysed; the working ranges of total and glycated haemoglobin were 50-2000 and 10-90 microg/ml, respectively. The developed method was successfully evaluated on blood samples collected from diabetics.

• MeSH
• biosenzitivní techniky * MeSH
• glykovaný hemoglobin analýza   chemie   MeSH
• hemoglobiny analýza   chemie   MeSH
• kyseliny boronové MeSH
• lidé MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• 3-aminobenzeneboronic acid MeSH Prohlížeč
• glykovaný hemoglobin MeSH
• hemoglobiny MeSH
• kyseliny boronové MeSH