Study on PTFE superhydrophobic coating modified by IC@dMSNs and its enhanced antibacterial effect.

INTRODUCTION: Vascular catheter-related infections and thrombosis are common and may lead to serious complications after catheterization. Reducing the incidence of such infections has become a significant challenge. OBJECTIVES: This study aims to develop a super hydrophobic nanocomposite drug-loaded vascular catheter that can effectively resist bacterial infections and blood coagulation. METHODS: In this study, a SiO2 nanocoated PTFE (Polytetrafluoroethylene) catheter (PTFE-SiO2) was prepared and further optimized to prepare a SiO2 nanocoated PTFE catheter loaded with imipenem/cilastatin sodium (PTFE-IC@dMSNs). The catheters were characterized for performance, cell compatibility, anticoagulant performance, in vitro and in vivo antibacterial effect and biological safety. RESULTS: PTFE-IC@dMSNs catheter has efficient drug loading performance and drug release rate and has good cell compatibility and anticoagulant effect in vitro. Compared with the PTFE-SiO2 catheter, the inhibition ring of the PTFE-IC@dMSNs catheter against Escherichia coli increased from 3.98 mm2 to 4.56 mm2, and the antibacterial rate increased from about 50.8 % to 56.9 %, with a significant difference (p < 0.05). The antibacterial zone against Staphylococcus aureus increased from 8.63 mm2 to 11.74 mm2, and the antibacterial rate increased from approximately 83.5 % to 89.3 %, showing a significant difference (p < 0.05). PTFE-IC@dMSNs catheter also has good biocompatibility in vivo. Furthermore, the PTFE-IC@dMSNs catheter can reduce the adhesion of blood cells and have excellent anticoagulant properties, and even maintain these properties even with the addition of imipenem/cilastatin sodium. CONCLUSION: Compared with PTFE, PTFE-SiO2 and PTFE-IC@dMSNs catheters have good characterization performance, cell compatibility, and anticoagulant properties. PTFE SiO2 and PTFE-IC@dMSNs catheters have good antibacterial performance and tissue safety against E. coli and S. aureus. Relatively, PTFE-SiO2 and PTFE-IC@dMSNs catheter has better antibacterial properties and histocompatibility and has potential application prospects in anti-bacterial catheter development and anticoagulation.

Structural and functional analyses of an L-asparaginase from Geobacillus thermopakistaniensis.

Genome sequence of Geobacillus thermopakistaniensis contains an open reading frame annotated as a type II L-asparaginase (ASNaseGt). Critical structural analysis disclosed that ASNaseGt might be a type I L-asparaginase. In order to determine whether it is a type I or type II L-asparaginase, we have performed the structural-functional characterization of the recombinant protein as well as analyzed the localization of ASNaseGt in G. thermopakistaniensis. ASNaseGt exhibited optimal activity at 52 °C and pH 9.5. There was a > 3-fold increase in activity in the presence of ß-mercaptoethanol. Apparent Vmax and Km values were 2735 U/mg and 0.35 mM, respectively. ASNaseGt displayed high thermostability with >80 % residual activity even after 6 h of incubation at 55 °C. Recombinant ASNaseGt existed in oligomeric form. Addition of ß-mercaptoethanol lowered the degree of oligomerization and displayed that tetrameric form was the most active, with a specific activity of 4300 U/mg. Under physiological conditions, ASNaseGt displayed >50 % of the optimal activity. Localization studies in G. thermopakistaniensis revealed that ASNaseGt is a cytosolic protein. Structural and functional characterization, and localization in G. thermopakistaniensis displayed that ASNaseGt is not a type II but a type I L-asparaginase.

Outcomes of patients with elevated pulmonary artery systolic pressure on echocardiography due to chronic lung diseases.

BACKGROUND: Pulmonary hypertension is associated with increased mortality, and lung diseases are the second most common cause of pulmonary hypertension. We aimed to evaluate the prognostic value of echocardiography in low-middle income countries where right heart catheterization is difficult to perform. METHODS: This retrospective chart review study included adult patients hospitalized from June 2012 to May 2021, with a pulmonary artery systolic pressure (PASP) of ≥35 mmHg on echocardiography. The control arm consisted of patients with similar lung diseases who did not have an elevated PASP. RESULTS: The study and control arm consisted of 128 patients each, with both groups having similar lung diseases. Obesity hypoventilation syndrome was the most common etiology of elevated PASP (28.1 %), followed by pulmonary embolism (20.3 %). The overall 1-year mortality of the study cohort, after diagnosis of elevated PASP, was 20.3 %. The control cohort with normal PASP had a 1-year mortality of 4.7 %. In the study cohort, patients with bronchiectasis had the highest cause-specific 1-year mortality (45.5 %). In the normal PASP cohort, the highest cause-specific 1-year mortality was observed in patients with interstitial lung disease (13.0 %). One-year hospital readmission was observed in 46.9 % and 33.6 % of patients in the study and control arms, respectively. On multivariate analysis, increased odds of 1-year mortality were observed in patients with elevated PASP, patients with 1-year hospital readmission, and in patients with interstitial lung disease or bronchiectasis. CONCLUSION: Elevated PASP on echocardiography may be a prognostic factor for mortality in patients with chronic lung diseases.

Cobalt Uptake by Food Plants and Accumulation in Municipal Solid Waste Materials Compost-amended Soil: Public Health Implications.

One of the most pressing environmental issues is how to properly dispose of municipal solid waste (MSW), which represents both a substantial source of concern and a challenge. The current study evaluated cobalt (Co) accumulation in MSW, their uptake by different vegetables grown for two years, and related human health risks. Vegetables were grown in four different groups, such as one control (ground soil), and the remaining treatment groups (T1, T2, and T3) received varying concentrations of MSW. The analysis of Co was done through an atomic absorption spectrophotometer (AAS). Results revealed that the concentration of Co was higher in all the vegetables (n = 15) grown in soil supplemented with 75% MSW during 2nd growing year. Among all vegetables, the highest concentration of Co was observed in Solanum tuberosum at T3 during 2nd growing year. The pollution load index (PLI) value for vegetables during both growing years was more than 1 except in control soil. The findings indicated that the highest enrichment factor (EF) and hazard resilience index (HRI) value of 0.09 was present in S. tuberosum. Health index values for cobalt in the study were below 1. The HRI < 1 indicated that consumers do not face any immediate health risks. The investigation of Co concentrations in blood samples obtained from individuals residing in different areas contributes a human health perspective to the research. The findings indicate that the concentration of Co rises with an increasing proportion of MSW. While the metal levels in MSW-treated soil were not high enough to classify the soil as polluted, the results recommend that recycling MSW can substitute mineral fertilizers. Nevertheless, the presence of cobalt in MSW may directly affect soil fertility and could impact crop production and human health.

Molecular cloning and characterization of Pcal_0039, an ATP-/NAD+-independent DNA ligase from hyperthermophilic archaeon Pyrobaculum calidifontis.

The genome sequence of hyperthermophilic archaeon Pyrobaculum calidifontis contains an open reading frame, Pcal_0039, which encodes a putative DNA ligase. Structural analysis disclosed the presence of signature sequences of ATP-dependent DNA ligases. We have heterologously expressed Pcal_0039 gene in Escherichia coli. The recombinant protein, majorly produced in soluble form, was purified and functionally characterized. Recombinant Pcal_0039 displayed nick-joining activity between 40 and 85 °C. Optimal activity was observed at 70 °C and pH 5.5. Nick-joining activity was retained even after heating for 1 h at 90 °C, indicating highly thermostable nature of Pcal_0039. The nick-joining activity, displayed by Pcal_0039, was metal ion dependent and Mg2+ was the most preferred. NaCl and KCl inhibited the nick-joining activity at or above 200 mmol/L. The activity catalyzed by recombinant Pcal_0039 was independent of addition of ATP or NAD+ or any other nucleotide cofactor. A mismatch adjacent to the nick, either at 3'- or 5'-end, abolished the nick-joining activity. These characteristics make Pcal_0039 a potential candidate for applications in DNA diagnostics. To the best of our knowledge, Pcal_0039 is the only DNA ligase, characterized from genus Pyrobaculum, which exhibits optimum nick-joining activity at pH below 6.0 and independent of any nucleotide cofactor.

Polymorphic Analysis of Genes PADI4 (rs2240340, rs1748033) and HLA-DRB1 (rs2395175) in Arthritis Patients in Pakistani Population.

Genes are an important factor for the initiation of any disease. Many genes are associated with rheumatoid arthritis (RA) other than environmental factors. The main objective of the study was to evaluate the association of genes PADI4 (peptidylarginine deiminases 14) (rs2240340, rs1748033) and Human leukocyte antigen class II histocompatibility, D-related beta chain (HLA-DRB1) (rs2395175) polymorphisms in RA patients from Punjab, Pakistan. Blood samples of RA patients were collected from different hospitals of Sargodha. DNA was extracted, followed by PCR. Polymorphic analysis was performed in 300 rheumatoid arthritis patients and 300 healthy controls on PADI4 (rs2240340, rs1748033) and HLA-DRB1 (rs2395175). In PADI4 gene, both homozygous mutant genotype (TT) and heterozygous (CT) of SNP rs2240340 showed significant association by increasing the risk of RA up to two fold (OR 2.55; 95% CI 1.57-4.15; p = 0.0002). In case of rs1748033 polymorphism, homozygous mutant genotype (TT) showed significant association with RA by increasing the risk of disease up to three fold (OR 3.46; 95% CI 1.97-6.07; p = 0.0001), while heterozygous genotype (CT) of the same SNP showed significant association with RA by playing a protective role (OR 0.57; 95% CI 0.36-0.91; p = 0.0197). In HLA-DRB1 gene, homozygous mutant genotype (GG) of SNP rs2395175 showed no significant association with RA, while heterozygous genotype (AG) of the same SNP showed significant association with RA by playing a protective role (OR 0.44; 95% CI 0.27-0.71; p = 0.0009). Highly significance association of genes PADI4 (rs2240340, rs1748033) and HLA-DRB1 (rs2395175) polymorphisms with RA was observed in Pakistani population.

Functional analyses of a highly thermostable hexokinase from Pyrobaculum calidifontis.

The gene encoding a repressor open reading frame sugar kinase (ROK) family protein from hyperthermophilic crenarchaeon Pyrobaculum calidifontis, Pcal-HK, was cloned and expressed in Escherichia coli. The recombinant protein was produced in soluble and highly active form. Purified Pcal-HK was highly thermostable and existed in a monomeric form in solution. The enzyme was specific to ATP as phosphoryl donor but showed broad specificity to phosphoryl acceptors. It catalyzed the phosphorylation of a number of hexoses, including glucose, glucosamine, N-acetyl glucosamine, fructose and mannose, at nearly the same rate and similar affinity. The enzyme was metal ion dependent exhibiting highest activity at 90-95 °C and pH 8.5. Mg2+ was most effective metal ion, which could be partially replaced by Mn2+, Ni2+ or Zn2+. Kinetic parameters were determined at 90 °C and the enzyme showed almost similar catalytic efficiency (kcat/Km) towards the above mentioned hexoses. To the best of our knowledge, Pcal-HK is the most active thermostable ROK family hexokinase characterized to date which catalyzes the phosphorylation of various hexoses with nearly similar affinity.

Role of C-terminal domain in a manganese-catalase from Geobacillus thermopakistaniensis.

Catalases catalyze the decomposition of hydrogen peroxide into water and oxygen. We have characterized two manganese-catalases from Geobacillus thermopakistaniensis, CatGt and Cat-IIGt, which exhibited significant variation in their sequence, structure and properties. There was only 23% sequence identity between the two. The striking structural difference was the presence of an extended C-terminal domain in CatGt. Molecular modelling and docking studies revealed that deletion of the C-terminal domain removes non-specific binding, which results in increased substrate affinity. To verify experimentally, a C-terminal truncated version of CatGt, named as CatGt-ΔC, was produced in Escherichia coli and effects of deletion were analyzed. There was no significant difference in optimal pH, optimal temperature and substrate specificity of CatGt and CatGt-ΔC. However, Km value was reduced from 259 to 157 mM and CatGt-ΔC exhibited ∼1.5-fold higher catalytic efficiency as compared to CatGt. Furthermore, removal of the C-terminal domain converted the tetrameric nature to monomeric, and reduced the thermostability of the truncated protein. These results demonstrate that C-terminal domain of CatGt might have little role in maintaining enzyme function but provides additional structural stability to the protein, which is a desired property for industrial applications.

Therapeutical Significance of Serpina3n Subsequent Cerebral Ischemia via Cytotoxic Granzyme B Inactivation.

Ischemic stroke is a devastating CNS insult with few clinical cures. Poor understanding of underlying mechanistic network is the primary limitation to develop novel curative therapies. Extracellular accumulation of granzyme B subsequent ischemia promotes neurodegeneration. Inhibition of granzyme B can be one of the potent strategies to mitigate neuronal damage. In present study, we investigated the effect of murine Serpina3n and human (homolog) SERPINA3 against cerebral ischemia through granzyme B inactivation. Recombinant Serpina3n/SERPINA3 were expressed by transfected 293 T cells, and eluted proteins were examined for postischemic influence both in vitro and in vivo. During in vitro test, Serpina3n was found effective enough to inhibit granzyme B, while SERPINA3 was ineffectual to counter cytotoxic protease. Treatment of hypoxic culture with recombinant Serpina3n/SERPINA3 significantly increased cell viability in dosage-dependent manner, recorded maximum at the highest concentration (4 mM). Infarct volume analysis confirmed that 50 mg/kg dosage of exogenous Serpina3n was adequate to reduce disease severity, while SERPINA3 lacked behind in analeptic effect. Immunohistochemical test, western blot analysis, and protease activity assay's results illustrated successful diffusion of applied protein to the ischemic lesion and reactivity with the target protease. Taken together, our findings demonstrate therapeutic potential of Serpina3n by interfering granzyme B-mediated neuronal death subsequent cerebral ischemia.

Investigating the role of carbohydrate-binding module 34 in cyclomaltodextrinase from Geobacillus thermopakistaniensis: structural and functional analyses.

Carbohydrate-binding modules (CBMs) are noncatalytic regions found in several enzymes of glycoside hydrolase family 13 and are proposed to orient substrates to the catalytic site. In this study, a substantial information on the conserved aromatic residues in CBM34 regions of characterized bacterial cyclolmaltodextrinases (CDases) has been presented. Molecular modeling of CDase from Geobacillus thermopakistaniensis (CDase Gt ) revealed a change in the active site geometry due to CBM34 truncation. The binding energies of full-length (CDase Gt ) and CBM34 truncated (CDase Gt -ΔN) models showed opposite trends. The least preferred substrate molecule by the full-length model was the most preferred by the CBM34 truncated one. These exciting in silico findings were experimentally verified by recombinant production and characterization of the full-length and the CBM34 truncated proteins. Both the enzymes showed similar optimum pH and temperature. However, substrate specificity was in the reverse order. These experimental verifications matched the homology modeling and docking predictions. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s13205-021-03089-9.

Looking into a highly thermostable and efficient recombinant manganese-catalase from Geobacillusthermopakistaniensis.

Catalases, heme or non-heme, are catalysts that decompose hydrogen peroxide. Among them, non-heme or manganese-catalases have been studied from limited organisms. We report here heterologous production of a manganese-catalase, Cat-IIGt, previously annotated as a hypothetical protein, from a thermophilic bacterium Geobacillus thermopakistaniensis. Recombinant Cat-IIGt, produced as inactive inclusion bodies in Escherichia coli, was solubilized and refolded into a soluble and highly active form. Sequence homology, absorption spectra, resistance to sodium azide inhibition and activation by Mn2+ indicated that it was a manganese-catalase. Metal analysis revealed the presence of ∼2 Mn2+ and ∼2 Ca2+ per subunit of Cat-IIGt. Recombinant Cat-IIGt exhibited highest activity at pH 10.0 and 70°C. The enzyme was highly active with a specific activity of 40,529 µmol min-1 mg-1. The apparent Km and kcat values were 75 mM and 1.5 × 104 s-1 subunit-1, respectively. Recombinant Cat-IIGt was highly thermostable with a half-life of 30 min at 100°C. The structural attributes of Cat-IIGt, including the metal and substrate binding residues, were predicted by homology modeling and molecular docking studies. High activity and thermostability and alkaline nature make Cat-IIGt a potential candidate for textile and paper processing industries.

Effectiveness of Natural Antioxidants against SARS-CoV-2? Insights from the In-Silico World.

The SARS CoV-2 pandemic has affected millions of people around the globe. Despite many efforts to find some effective medicines against SARS CoV-2, no established therapeutics are available yet. The use of phytochemicals as antiviral agents provides hope against the proliferation of SARS-CoV-2. Several natural compounds were analyzed by virtual screening against six SARS CoV-2 protein targets using molecular docking simulations in the present study. More than a hundred plant-derived secondary metabolites have been docked, including alkaloids, flavonoids, coumarins, and steroids. SARS CoV-2 protein targets include Main protease (MPro), Papain-like protease (PLpro), RNA-dependent RNA polymerase (RdRp), Spike glycoprotein (S), Helicase (Nsp13), and E-Channel protein. Phytochemicals were evaluated by molecular docking, and MD simulations were performed using the YASARA structure using a modified genetic algorithm and AMBER03 force field. Binding energies and dissociation constants allowed the identification of potentially active compounds. Ligand-protein interactions provide an insight into the mechanism and potential of identified compounds. Glycyrrhizin and its metabolite 18-ß-glycyrrhetinic acid have shown a strong binding affinity for MPro, helicase, RdRp, spike, and E-channel proteins, while a flavonoid Baicalin also strongly binds against PLpro and RdRp. The use of identified phytochemicals may help to speed up the drug development and provide natural protection against SARS-CoV-2.

Structural and functional analyses of a novel manganese-catalase from Bacillus subtilis R5.

Catalases catalyze the decomposition of hydrogen peroxide into water and oxygen. Limited reports are available on characterization of manganese-catalases. We describe here molecular cloning and expression in Escherichia coli of a putative manganese-catalase gene from mesophilic bacterium, Bacillus subtilis R5. The gene product, CatBsu, produced as a soluble protein, was purified to apparent homogeneity and biochemically characterized. The absorption spectra and nonsignificant inhibition by sodium azide indicated that it is a manganese-catalase. The protein was in homohexameric form in solution, with a subunit molecular weight of 30 kDa, containing ~2 Mn2+ and ~1 Ca2+ per subunit. CatBsu showed highest activity at pH 8.0 and 55 °C. It was found to be highly active with a specific activity of 25,290 µmol min-1 mg-1 and apparent Km and kcat values of 98 mM and 1.27 × 104 s-1 subunit-1, respectively. Although from a mesophilic source, it exhibited a half-life of 2 h at 80 °C. Furthermore, the active site and metal binding residues in CatBsu were predicted by homology modelling and molecular docking. To the best of our knowledge, this is the first characterization of a manganese-catalase from genus Bacillus.

ADP-dependent glucose/glucosamine kinase from Thermococcus kodakarensis: cloning and characterization.

The genome sequence of Thermococcus kodakarensis contains an open reading frame, TK1110, annotated as ADP-dependent glucokinase. The encoding gene was expressed in Escherichia coli and the gene product, TK-GLK, was produced in soluble and active form. The recombinant enzyme was extremely thermostable. Thermostability was increased significantly in the presence of ammonium sulfate. ADP was the preferred co-factor for TK-GLK, which could be replaced with CDP but with a 60% activity. TK-GLK was a metal ion-dependent enzyme which exhibited glucokinase, glucosamine kinase and glucose 6-phosphatase activities. It catalyzed the phosphorylation of both glucose and glucosamine with nearly the same rate and affinity. The apparent Km values for glucose and glucosamine were 0.48 ± 0.03 and 0.47 ± 0.09 mM, respectively. The catalytic efficiency (kcat/Km) values against these two substrates were 6.2 × 105 ± 0.25 and 5.8 × 105 ± 0.75 M-1 s-1. The apparent Km value for dephosphorylation of glucose 6-phosphate was ~14-fold higher than that of glucose phosphorylation. Similarly, catalytic efficiency (kcat/Km) for phosphatase reaction was ~19-fold lower than that for the kinase reaction. To the best of our knowledge, this is the first report that describes the reversible nature of a euryarchaeal ADP-dependent glucokinase.

Coal Dust-Induced Systematic Hypoxia and Redox Imbalance among Coal Mine Workers.

Continuous inhalation of coal dust among coal workers leads to a variety of disorders. The present study aims to evaluate the potential oxidative stress associated with coal dust generated from coal mining activities among exposed workers through the antioxidant enzyme system, including superoxide dismutase (SOD), catalase (CAT), and glutathione (GSH). In this study cohort, intensive coal mine workers were assessed for antioxidant variations. Blood samples were collected from dust-exposed workers (engaged in different activities at coal mines; n = 311) and residents of the same city (nonexposed, control group; n = 50). The workers' exposure to coal dust was categorized based on working area (administrative group, surface workers, underground workers), working hours (up to 8 h and more than 8 h), and time of service. The results showed significantly altered activities of SOD, CAT, and GSH among the whole exposed group and its categories compared to the control group. A significant difference was also observed between high- and low-exposure groups. Statistical analysis revealed a negative correlation between antioxidant activity (catalase and SOD) and coal dust levels. Besides, coal exposure was associated with the time of service, smoking status, and dietary habits. The findings of this study reveal higher oxidative stress among highly exposed coal mine workers (underground workers > surface workers > administrative group > nonexposed group), and longer working hours have more pronounced adverse effects on workers' health.

An overview of 25 years of research on Thermococcus kodakarensis, a genetically versatile model organism for archaeal research.

Almost 25 years have passed since the discovery of a planktonic, heterotrophic, hyperthermophilic archaeon named Thermococcus kodakarensis KOD1, previously known as Pyrococcus sp. KOD1, by Imanaka and coworkers. T. kodakarensis is one of the most studied archaeon in terms of metabolic pathways, available genomic resources, established genetic engineering techniques, reporter constructs, in vitro transcription/translation machinery, and gene expression/gene knockout systems. In addition to all these, ease of growth using various carbon sources makes it a facile archaeal model organism. Here, in this review, an attempt is made to reflect what we have learnt from this hyperthermophilic archaeon.

Biochemical characterization of a highly active ADP-dependent phosphofructokinase from Thermococcus kodakarensis.

The genome sequence of Thermococcus kodakarensis contains an open reading frame, TK0376, annotated as ADP-dependent phosphofructokinase belonging to pfkC family. The encoding gene was expressed in Escherichia coli and the gene product was characterized. The recombinant protein was produced in soluble and active form. Phosphofructokinase activity of TK0376 was metal-ion dependent and the highest activity (5090 µmol min-1 mg-1) was found in the presence of Co2+ followed by Mg2+ (3280 µmol min-1 mg-1) at 90°C and pH 7.5. TK0376 preferred ADP as phosphoryl donor, however, it could be replaced by ATP but with a 5-fold lower activity. It catalyzed the phosphorylation of fructose 6-phosphate and dephosphorylation of fructose 1,6-bisphosphate. In addition, it was able to phosphorylate glucose and nucleosides but with a much lower rate compared to that of fructose 6-phosphate. The apparent kcat and Km values against fructose 6-phosphate were 4238 s-1 and 0.74 mM, respectively. The rate of dephosphorylation of fructose 1,6-bisphosphate was 3-times lower at 50°C than the phosphorylation of fructose 6-phosphate. Similarly, the rate of phosphorylation of glucose was 450-fold lower than that of fructose 6-phosphate. Phosphofructokinase activity was not allosterically regulated, but it was slightly enhanced by phosphoenol pyruvate, and inhibited by ATP and AMP in a competitive manner.

Serpina3n: Potential drug and challenges, mini review.

Serpina3n is a secretory serine protease inhibitor belonging to clade "a" exhibiting unique structural and physiological characteristics, playing significant roles ranging from complement cascade, apoptosis, wound healing to Alzheimer by inhibiting a wide range of proteases. Recently studies have reported its significant roles during various pathologies. Although its full range of potential applications are yet to reveal, its reported implications particularly in CNS insults are making it potential therapeutical approach. Here we aim to draw together the literature shedding light on the potential therapeutical applications of Serpina3n/SERPINA3 in various diseases and a brief comparison between murine Serpina3n and its human ortholog SERPINA3 (α1-antichymotrypsin) accounting their biological roles and significance.

A highly stable manganese catalase from Geobacillus thermopakistaniensis: molecular cloning and characterization.

Catalases, heme or manganese, are efficient biocatalysts that split hydrogen peroxide into water and oxygen. We have cloned a manganese catalase from thermophilic bacterium, Geobacillus thermopakistaniensis, and expressed the corresponding gene in Escherichia coli. The gene product, CatGt, was synthesized in E. coli as inactive inclusion bodies. Solubilization and refolding of the inclusion bodies resulted in highly active CatGt with a specific activity of 18,521 µmol min-1 mg-1. The refolded protein exhibited apparent Km and kcat values of 260 mM and 10,360 s-1 subunit-1, respectively. It exhibited a half-life of 1 h at 100 °C. The unique features of CatGt are its high activity and thermostability. These features make it a valuable catalyst for industrial applications. To the best of our knowledge, CatGt is the most thermostable catalases characterized to date.