An amperometric biosensor compatible with a flow injection analysis (FIA) for highly selective determination of acetaminophen (APAP) in a sample of human urine was developed. This biosensor is also suitable for use in the routine pharmaceutical practice. To prove this statement, two different commercially available pharmaceutical formulations were analyzed. This nano-(bio)electroanalytical device was made from a commercially available screen-printed carbon electrode covered by a thin layer of non-functionalized graphene (NFG) as amperometric transducer. A biorecognition layer was prepared from mushroom (Agaricus bisporus) tyrosinase (EC 1.14.18.1) cross-linked using glutaraldehyde, where resulting aggregates were covered by Nafion®, a known ion exchange membrane. Owing to the use of tyrosinase and presence of NFG, the developed analytical instrument is able to measure even at potentials of 0 V. Linear ranges differ according to choice of detection potential, namely up to 130 μmol L-1 at 0 V, up to 90 μmol L-1 at -0.1 V, and up to 70 μmol L-1 at -0.15 V. The first mentioned linear range is described by the equation Ip [μA] = 0.236 - 0.1984c [μmol L-1] and correlation coefficient r = 0.9987; this equation was used to quantify the content of APAP in each sample. The limit of detection of APAP was estimated to be 1.1 μmol L-1. A recovery of 96.8% (c = 25 μmol L-1, n = 5 measurements) was calculated. The obtained results show that FIA is a very selective method for APAP determination, being comparable to the chosen reference method of reversed-phase high-performance liquid chromatography.

• MeSH
• Agaricus enzymologie   MeSH
• analýza moči přístrojové vybavení   metody   MeSH
• biosenzitivní techniky přístrojové vybavení   metody   MeSH
• design vybavení MeSH
• lidé MeSH
• limita detekce MeSH
• neopioidní analgetika moč   MeSH
• paracetamol moč   MeSH
• průtoková injekční analýza přístrojové vybavení   metody   MeSH
• tyrosinasa chemie   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• hodnotící studie MeSH

The enzyme immobilization is a very important process providing an attachment of the enzyme to a certain type of the carrier. This allows to maintain the enzyme activity during the storage and it also simplifies the detection procedure. When designing a new detector based on the enzymatic reaction, the proper immobilization method must be chosen depending on the advantages and disadvantages of the available methods of immobilization. Examples of immobilization method for colorimetric detection include, e.g., adsorption to the insoluble carrier, covalent bonding, attachment to ion exchangers, incorporation into gels and foams, immobilization in the form of cross-linked aggregates or nanostructures or with the utilization of antibodies.

• Klíčová slova
• kovalentní vazba,
• MeSH
• adsorpce MeSH
• cholinesterasové inhibitory MeSH
• cholinesterasy MeSH
• enzymy * MeSH
• gely analýza   chemie   MeSH
• imobilizace * metody   přístrojové vybavení   MeSH
• Publikační typ
• práce podpořená grantem MeSH

Ligninolytic enzymes from white-rot fungi are widely used in biotechnological processes. However, the application of these enzymes as free enzymes is limited due to their instability and lack of reusability. Enzyme stabilization is therefore a major challenge in biocatalytic process research, and immobilization methods are desirable. Using cross-linked enzyme aggregates (CLEAs) such as magnetic CLEAs, porous-CLEAs and combi-CLEAs is a promising technique for overcoming these issues. Cross-linking methods can stabilize and immobilize enzymes by interconnecting enzyme molecules via multiple bonds using cross-linking agents such as glutaraldehyde. The high catalyst density and microporous assembly of CLEAs guarantee high catalyst activity, which, together with their long shelf life, operational stability, and reusability, provide a cost-efficient alternative to matrix-assisted immobilization approaches. Here, we review current progress in ligninolytic enzyme immobilization and provide a comprehensive review of CLEAs. Moreover, we summarize the use of these CLEAs for biocatalysis processes, bioremediation such as dye decolourization, wastewater treatment or pharmaceutically active compound elimination.

• MeSH
• biokatalýza MeSH
• enzymy imobilizované chemie   MeSH
• glutaraldehyd chemie   MeSH
• houby enzymologie   MeSH
• lignin metabolismus   MeSH
• peroxidasy chemie   MeSH
• reagencia zkříženě vázaná chemie   MeSH
• stabilita enzymů MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH

The key to obtaining an optimum performance of an enzyme is often a question of devising a suitable enzyme and optimisation of conditions for its immobilization. In this study, laccases from the native isolates of white rot fungi Fomes fomentarius and/or Trametes versicolor, obtained from Czech forests, were used. From these, cross-linked enzyme aggregates (CLEA) were prepared and characterised when the experimental conditions were optimized. Based on the optimization steps, saturated ammonium sulphate solution (75 wt.%) was used as the precipitating agent, and different concentrations of glutaraldehyde as a cross-linking agent were investigated. CLEA aggregates formed under the optimal conditions showed higher catalytic efficiency and stabilities (thermal, pH, and storage, against denaturation) as well as high reusability compared to free laccase for both fungal strains. The best concentration of glutaraldehyde seemed to be 50 mM and higher efficiency of cross-linking was observed at a low temperature 4 °C. An insignificant increase in optimum pH for CLEA laccases with respect to free laccases for both fungi was observed. The results show that the optimum temperature for both free laccase and CLEA laccase was 35 °C for T. versicolor and 30 °C for F. fomentarius. The CLEAs retained 80% of their initial activity for Trametes and 74% for Fomes after 70 days of cultivation. Prepared cross-linked enzyme aggregates were also investigated for their decolourisation activity on malachite green, bromothymol blue, and methyl red dyes. Immobilised CLEA laccase from Trametes versicolor showed 95% decolourisation potential and CLEA from Fomes fomentarius demonstrated 90% decolourisation efficiency within 10 h for all dyes used. These results suggest that these CLEAs have promising potential in dye decolourisation.

• MeSH
• azosloučeniny chemie   MeSH
• barva MeSH
• barvicí látky chemie   MeSH
• bromthymolová modř chemie   MeSH
• enzymy imobilizované chemie   MeSH
• glutaraldehyd chemie   MeSH
• katalýza MeSH
• lakasa chemie   MeSH
• Polyporales enzymologie   MeSH
• reagencia zkříženě vázaná chemie   MeSH
• rosanilinová barviva chemie   MeSH
• síran amonný chemie   MeSH
• teplota MeSH
• Trametes enzymologie   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

"As the amount of information in biology expands dramatically, it becomes increasingly important for textbooks to distill the vast amount of scientific knowledge into concise principles and enduring concepts. As with previous editions, Molecular Biology of the Cell, Sixth Edition accomplishes this goal with clear writing and beautiful illustrations. The Sixth Edition has been extensively revised and updated with the latest research in the field of cell biology, and it provides an exceptional framework for teaching and learning. The entire illustration program has been greatly enhanced. Protein structures better illustrate structure-function relationships, icons are simpler and more consistent within and between chapters, and micrographs have been refreshed and updated with newer, clearer, or better images. As a new feature, each chapter now contains intriguing open-ended questions highlighting "What We Don't Know," introducing students to challenging areas of future research. Updated end-of-chapter problems reflect new research discussed in the text. Thought-provoking end-of-chapter questions have been expanded to all chapters, including questions on developmental biology, tissues and stem cells, the immune system, and pathogens"--Provided by publisher.

• MeSH
• buňky * MeSH
• molekulární biologie MeSH

• Konspekt
• Biochemie. Molekulární biologie. Biofyzika
• NLK Obory
• molekulární biologie, molekulární medicína
• NLK Publikační typ
• učebnice vysokých škol

Enzymes have a wide range of applications in different industries owing to their high specificity and efficiency. Immobilization is often used to improve biocatalyst properties, operational stability, and reusability. However, changes in the structure of biocatalysts during immobilization and under process conditions are still largely uncertain. Here, three microscopy techniques - bright-field, confocal and electron microscopy - were applied to determine the distribution and structure of an immobilized biocatalyst. Free enzyme (haloalkane dehalogenase), cross-linked enzyme aggregates (CLEAs) and CLEAs entrapped in polyvinyl alcohol lenses (lentikats) were used as model systems. Electron microscopy revealed that sonicated CLEAs underwent morphological changes that strongly correlated with increased catalytic activity compared to less structured, non-treated CLEAs. Confocal microscopy confirmed that loading of the biocatalyst was not the only factor affecting the catalytic activity of the lentikats. Confocal microscopy also showed a significant reduction in the pore size of lentikats exposed to 25% tetrahydrofuran and 50% dioxane. Narrow pores appeared to provide protection to CLEAs from the detrimental action of cosolvents, which significantly correlated with higher activity of CLEAs compared to free enzyme. The results showed that microscopy can provide valuable information about the structure and properties of a biocatalyst during immobilization and under process conditions.

• MeSH
• biokatalýza MeSH
• dioxany farmakologie   MeSH
• furany farmakologie   MeSH
• hydrolasy chemie   metabolismus   MeSH
• mikroskopie metody   MeSH
• proteiny červů chemie   metabolismus   MeSH
• Schistosoma japonicum enzymologie   MeSH
• stabilita enzymů MeSH
• vztahy mezi strukturou a aktivitou MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Glycation is a process closely related to the aging and pathogenesis of diabetic complications. In this process, reactive α-dicarbonyl compounds (e.g., methylglyoxal) cause protein modification accompanied with potential loss of their biological activity and persistence of damaged molecules in tissues. We suppose that glutathione S-transferases (GSTs), a group of cytosolic biotransformation enzymes, may be modified by glycation in vivo, which would provide a rationale of its use as a model protein for studying glycation reactions. Glycation of GST by methylglyoxal, fructose, and glucose in vitro was studied. The course of protein glycation was evaluated using the following criteria: enzyme activity, formation of advanced glycation end-products using fluorescence and western blotting, amine content, protein conformation, cross linking and aggregation, and changes in molecular charge of GST. The ongoing glycation by methylglyoxal 2 mM resulted in pronounced decrease in the GST activity. It also led to the loss of 14 primary amino groups, which was accompanied by changes in protein mobility during native polyacrylamide gel electrophoresis. Formation of cross links with molecular weight of 75 kDa was observed. Obtained results can contribute to understanding of changes, which proceed in metabolism of xenobiotics during diabetes mellitus and ageing.

• MeSH
• diabetes mellitus enzymologie   MeSH
• fruktosa chemie   metabolismus   MeSH
• glukosa chemie   metabolismus   MeSH
• glutathiontransferasa chemie   metabolismus   MeSH
• katalýza MeSH
• lidé MeSH
• produkty pokročilé glykace chemie   metabolismus   MeSH
• pyruvaldehyd chemie   metabolismus   MeSH
• stárnutí metabolismus   MeSH
• xenobiotika chemie   metabolismus   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• srovnávací studie MeSH

• MeSH
• dítě MeSH
• krevní nemoci MeSH
• novorozenec MeSH
• Check Tag
• dítě MeSH
• novorozenec MeSH
• Publikační typ
• sborníky MeSH

• Konspekt
• Patologie. Klinická medicína
• NLK Obory
• onkologie
• hematologie a transfuzní lékařství

• MeSH
• biologie buňky MeSH
• molekulární biologie MeSH
• Publikační typ
• monografie MeSH

• Konspekt
• Biochemie. Molekulární biologie. Biofyzika
• NLK Obory
• biologie
• cytologie, klinická cytologie