Nanomaterials that exhibit enzyme-like activity (nanozymes) have attracted significant attention due to their potential for applications in analytical tests and in the biological field. In this ...study, an enzyme-like nanomaterial is developed by coupling Pt nanoparticles with WO.sub.2.72 (Pt/WO.sub.2.72). The resultant nanocomposite nanomaterial exhibits peroxidase activity and catalase activity. Moreover, owing to the presence of W.sup.6+ and W.sup.5+ in WO.sub.2.72, Pt/WO.sub.2.72 nanoplates demonstrate promise as scavengers of hydroxyl radicals. The Pt/WO.sub.2.72 composite nanoplates exhibit excellent peroxidase-like activity for the sensitive colorimetric detection of H.sub.2O.sub.2 and blood glucose. These Pt/WO.sub.2.72 nanoplates are thought to be a promising tool for broad potential applications in biomedicine, biotechnology, and environmental chemistry.
Immobilisation plays an important role in the industrial application of enzymes. The stabilisation and reusability of immobilised enzymes reduce the cost of the catalyst and facilitate their use in ...continuously operated reactors. For this purpose, an applicable type of immobilisation needs to be identified. In this study, we investigate the conversion of CDP and PolyP to CTP by NDP polyphosphate phosphotransferase 3 from Ruegeria pomeroyi (RpPPK2-3) and describe the covalent immobilisation of RpPPK2-3. In order to select a suitable carrier for the immobilisation of RpPPK2-3, a screening with different amino methacrylate (glutaraldehyde-pre-activated) and epoxy methacrylate carriers was carried out. The epoxy methacrylate carrier ECR8209M (Purolitesup.®) was found to be the most suitable. With a half-life of 462 d when stored at 6 °C and a 50-fold reusability with a 93% residual activity, the immobilised enzyme showed a higher stability compared to the soluble enzyme with a half-life of 0.04 d. Although the half-life of the soluble enzyme could be increased to 32 d by adding PPsub.i, it could not reach the stability of the immobilisate. Due to the resilience of the immobilisate, it is suitable for application in continuous reactor set-ups, e.g., packed-bed reactors.
Butyl oleate synthesis by the lipase B from Candida antarctica (CalB) under extreme halophilic conditions was investigated in the present research through the AOT/Water/Isooctane reverse micellar ...system. The impact of aqueous content (Wsub.o=H2O/Surfactant) and NaCl variation on the enzymatic activity of CalB in the butyl oleate reaction in reverse micelles was explored. The results indicated that, based on the increase of NaCl, it is remarkable to achieve higher enzymatic activity up to 444.85 μmol/min at 5 M NaCl and Wo = 10, as the best esterification conditions at pH 7.2 and 30 °C. However, it was clear that butyl oleate synthesis by lipase CalB increased based on the reduction in the average reverse micelle size, where reverse micelle sizes were determined by dynamic light scattering (DLS). This increase in butyl oleate synthesis demonstrated the potential of reverse micelles as systems that enhance mass transport phenomena in heterogeneous biocatalysis. Furthermore, reverse micelles are promising systems for extreme halophilic lipases research.
The immobilization of proteins (mostly typically enzymes) onto solid supports is mature technology and has been used successfully to enhance biocatalytic processes in a wide range of industrial ...applications. However, continued developments in immobilization technology have led to more sophisticated and specialized applications of the process. A combination of targeted chemistries, for both the support and the protein, sometimes in combination with additional chemical and/or genetic engineering, has led to the development of methods for the modification of protein functional properties, for enhancing protein stability and for the recovery of specific proteins from complex mixtures. In particular, the development of effective methods for immobilizing large multi-subunit proteins with multiple covalent linkages (multi-point immobilization) has been effective in stabilizing proteins where subunit dissociation is the initial step in enzyme inactivation. In some instances, multiple benefits are achievable in a single process.
Here we comprehensively review the literature pertaining to immobilization and chemical modification of different enzyme classes from thermophiles, with emphasis on the chemistries involved and their implications for modification of the enzyme functional properties. We also highlight the potential for synergies in the combined use of immobilization and other chemical modifications.
Penicillium species are ubiquitous in the environment and are of substantial importance, especially in industrial and medical aspects. During our investigation of the biodiversity of Penicillium, ...three new species were discovered in soil samples collected from East and Northeast China. They were determined as new to science based on morphological comparisons and phylogenetic analyses, and were found to belong to the subgenus Penicillium section Robsamsonia and subgenus Aspergilloides sections Aspergilloides and Citrina. Descriptions and illustrations of these species are provided, and their geographic distributions are also discussed.
In this study, Chlorella pyrenoidosa was cultured with different concentrations of Cr(III) and Cr(VI), and the changes in biomass, lipid content, protein content and total sugar content of Chlorella ...pyrenoidosa under different culture conditions were detected. The effects of Cr(III) and Cr(VI) on the intracellular antioxidant system and related key enzymes of lipid synthesis were analyzed. The results showed that appropriate Cr(III) and Cr(VI) concentrations could make Chlorella pyrenoidosa regulate the contents of SOD, POD, ASA, CAT and GSH in cells, improve the enzyme activity of ACC and promote lipid synthesis. The aim was to investigate the mechanism of lipid synthesis by analyzing the distribution of Cr(III) and Cr(VI) in algal cells. The lipid content of Chlorella pyrenoidosa reached its highest level at 50.43 wt% and 38.00 wt% when both Cr(III) and Cr(VI) concentrations in the culture environment were 0.5 mg/L. These values were 1.37 and 1.03 times higher than the control group, respectively. The addition of appropriate Cr(III) and Cr(VI) concentrations can increase ME enzyme activity and decrease PEPC enzyme activity, shorten the biomass accumulation cycle and prolong the lipid synthesis cycle.
Mesoporous materials as support for immobilized enzymes have been explored extensively during the last two decades, primarily not only for biocatalysis applications, but also for biosensing, biofuels ...and enzyme-controlled drug delivery. The activity of the immobilized enzymes inside the pores is often different compared to that of the free enzymes, and an important challenge is to understand how the immobilization affects the enzymes in order to design immobilization conditions that lead to optimal enzyme activity. This review summarizes methods that can be used to understand how material properties can be linked to changes in enzyme activity. Real-time monitoring of the immobilization process and techniques that demonstrate that the enzymes are located inside the pores is discussed by contrasting them to the common practice of indirectly measuring the depletion of the protein concentration or enzyme activity in the surrounding bulk phase. We propose that pore filling (pore volume fraction occupied by proteins) is the best standard for comparing the amount of immobilized enzymes at the molecular level, and present equations to calculate pore filling from the more commonly reported immobilized mass. Methods to detect changes in enzyme structure upon immobilization and to study the microenvironment inside the pores are discussed in detail. Combining the knowledge generated from these methodologies should aid in rationally designing biocatalyst based on enzymes immobilized in mesoporous materials.
Display omitted
•Calculating pore filling as standard for comparing different mesoporous particles•Techniques for real time study of the immobilization process•Visualization of enzymes in the pores by microscopy•Methods for studying conformational changes of enzymes•Study of the microenvironment inside the pores as a function of material properties
The problem of acute organophosphorus poisoning is far from control. Erythrocyte cholinesterase (AChE) is considered as a gold standard biomarker of such poisoning. However, activity measurement of ...AChE is of limited use as the enzyme activity exhibits intra and inters individual variations. For all practical purpose, the baseline value of the enzyme is not known. Therefore, development of a baseline independent assay of the enzyme activity is of recent concern. In this context, we have observed that reactivation based method development is possible, which will provide baseline independent, personalized assessment of the enzyme activity. We have observed using tools of computational biology that the interaction of the established non-oxime reactivators (NOR)with the classical enzyme substrate is more than oximate ion. This leads us to predict that the lysis of the classical enzyme substrate will be more in the presence of NORs in comparison to oximolysis. Keeping the importance of the baseline independent assay development in mind, we feel that our data is going to help the researchers in the field.
Lead and Hypoxia Venkatesh, Thuppil
Indian journal of clinical biochemistry,
05/2022, Volume:
34, Issue:
S1
Journal Article
Peer reviewed
Lead is number one environmental poison to all forms of life even for high altitude dwellings. Lead is also used in paints, pigments and in traditional medicines apart the production of various ...cosmetics used by high landers who were using natural dyes earlier. Of late one of the major source of lead to high landers is from UPS batteries. Lead is known to have deleterious effects on antioxidant enzymes. Work carried out by the authors on the blood lead levels have indicated the elevated blood lead levels in many high landers. Elevated BLL is also found to have an impact on the Intelligent Quotient (IQ). Author has found that most of the vegetable dyes used for dyeing and for of age old Thanka paintings by Tibetan high landers are being replaced by synthetic dyes resulting in high exposure to lead. Though many studies indicate that younger children involved in Thanka paintings have disturbed cognitive functions resulting in imperfect art work. And lack of attention.
