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#34130214   2021/06/08 To Up

Lectins: Biological significance to biotechnological application.

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Dixita Chettri, Manswama Boro, Lija Sarkar, Anil Kumar Verma

1362 related Products with: Lectins: Biological significance to biotechnological application.

0.1ml (1.3mg/ml) 100ul 100ul 100ul 100ul 100ul 100ul 100ul0.1ml (1mg/ml)100ug Lyophilized0.1ml (1mg/ml)100ug Lyophilized

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#34129928   2021/06/12 To Up

Global Reach 2018: nitric oxide-mediated cutaneous vasodilation is reduced in chronic, but not acute, hypoxia independently of enzymatic superoxide formation.

We tested the hypotheses that 1) cutaneous microvascular function is impaired by acute normobaric and chronic hypobaric hypoxia and 2) that the superoxide free radical (via NADPH oxidase or xanthine oxidase) contributes to this impairment via nitric oxide (NO) scavenging. Local heating-induced cutaneous hyperemia (39°C) was measured in the forearm of 11 male lowlanders at sea level (SL) and following 14-18 days at high altitude (HA; 4340 m in Cerro de Pasco, Peru), and compared to 11 highlanders residing permanently at this elevation. Cutaneous vascular conductance (CVC; laser-Doppler flux/mean arterial pressure) was not different during 39°C [control site: 73 (19) vs. 71 (18)%max; P=0.68] between normoxia and acute normobaric hypoxia (FO=0.125; equivalent to HA), respectively. At HA, CVC was reduced during 39°C in lowlanders compared to SL [control site: 54 (14) vs. 73 (19)%max; P<0.01] and was lower in Andean highlanders compared to lowlanders at HA [control site: 50 (24) vs. 54 (14)%max; P=0.02]. The NO contribution to vasodilation during 39°C (i.e., effect of NO synthase inhibition) was reduced in lowlanders at HA compared to SL [control site: 41 (11) vs 49 (10)%max; P=0.04] and in Andean highlanders compared to lowlanders at HA [control site: 32 (21) vs. 41 (11)%max; P=0.01]. Intradermal administration (cutaneous microdialysis) of the superoxide mimetic Tempol, inhibition of xanthine oxidase (via allopurinol), or NADPH oxidase (via apocynin) had no influence on cutaneous endothelium-dependent dilation during any of the conditions (all main effects of drug P>0.05). These results suggest that time at HA impairs NO-mediated cutaneous vasodilation independent of enzymatic superoxide formation.
Geoff B Coombs, John D Akins, Jordan C Patik, Gustavo A Vizcardo-Galindo, Romulo Figueroa-Mujica, Michael M Tymko, Benjamin S Stacey, Angelo Iannetelli, Damian M Bailey, Francisco C Villafuerte, Philip N Ainslie, R Matthew Brothers

2824 related Products with: Global Reach 2018: nitric oxide-mediated cutaneous vasodilation is reduced in chronic, but not acute, hypoxia independently of enzymatic superoxide formation.

100 96tests100ug Lyophilized0.1ml100ug Lyophilized100ug Lyophilized100ug Lyophilized100ug Lyophilized100ug Lyophilized100ug Lyophilized100ug Lyophilized

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#34129927   2021/06/12 To Up

Browsing the oldest antioxidant enzyme: catalase and its multiple regulation in cancer.

Aerobic organisms possess numerous antioxidant enzymatic families, including catalases, superoxide dismutases (SODs), peroxiredoxins (PRDXs), and glutathione peroxidases (GPXs), which work cooperatively to protect cells from an excess of reactive oxygen species (ROS) derived from endogenous metabolism or external microenvironment. Catalase, as well as other antioxidant enzymes, plays an important dichotomous role in cancer. Therefore, therapies aimed at either reverting the increased or further escalating catalase levels could be effective, depending on the metabolic landscape and on the redox status of cancer cells. This dichotomous role of catalase in cancers highlights the importance to deepen comprehensively the role and the regulation of this crucial antioxidant enzyme. The present review highlights the role of catalase in cancer and provides a comprehensive description of the molecular mechanisms associated with the multiple levels of catalase regulation.
Marilisa Galasso, Simona Gambino, Maria Grazia Romanelli, Massimo Donadelli, Maria Teresa Scupoli

2634 related Products with: Browsing the oldest antioxidant enzyme: catalase and its multiple regulation in cancer.



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#34129873   2021/06/12 To Up

IN VIVO IMMOBILIZED CARBONIC ANHYDRASE AND ITS EFFECT ON THE ENHANCEMENT OF CO ABSORPTION RATE.

Reactive absorption into aqueous solutions promoted by carbonic anhydrase (CA, E.C. 4.2.1.1.) has been often proposed as a post-combustion CO capture process. The state of the art reveals the need for efficient biocatalyst based on carbonic anhydrase that can be used to further develop CO capture and utilization technologies. The present study is focused on the use of a thermostable CA-based biocatalyst. The carbonic anhydrase SspCA, from the thermophilic bacterium Sulfurihydrogenibium yellowstonense, was in vivo immobilized as membrane-anchored protein (INPN-SspCA) on the outer membrane of Escherichia coli cells. The dispersed biocatalyst, made by cell membrane debris, was characterized in terms of its contribution to the enhancement of CO absorption in carbonate/bicarbonate alkaline buffer at operating conditions relevant for industrial CO capture processes. The amount of immobilized enzyme, estimated by SDS-PAGE, resulted in about 1 mg enzyme/g membrane debris. The apparent kinetics of the biocatalyst was characterized through CO absorption tests in a stirred cell lab-scale reactor assuming a pseudo-homogeneous behaviour of the biocatalyst. At 25 °C, the assessed values of the second-order kinetic constant ranged between 0.176 and 0.555 L∙mg∙s. Reusability of the biocatalyst after 24 h showed the absence of free enzyme release in the buffer. Moreover, the equilibration of dispersed cell membrane debris against the alkaline buffer positively affected the performances of the heterogeneous biocatalyst. These results encourage further studies on the in vivo immobilized SspCA aimed at optimizing the enzyme loading on the cell membrane and the handling of the biocatalyst in the CO absorption reactors.
S Fabbricino, S Del Prete, M E Russo, C Capasso, A Marzocchella, P Salatino

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1100ug

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#34129275   2021/06/15 To Up

Discovery of Novel Bacterial Chalcone Isomerases by a Sequence-Structure-Function-Evolution Strategy for Enzymatic Synthesis of (S)-Flavanones.

Chalcone isomerase (CHI) is a key enzyme in the biosynthesis of flavonoids in plants. The first bacterial CHI (CHIera) was identified from Eubacterium ramulus, but its distribution, evolutionary source, substrate scope, and stereoselectivity are still unclear. Here, we describe the identification of 66 novel bacterial CHIs from Genbank using a novel Sequence-Structure-Function-Evolution (SSFE) strategy. These novel bacterial CHIs show diversity in substrate specificity towards various hydroxylated and methoxylated chalcones. The mutagenesis of CHIera according to the substrate binding models of these novel bacterial CHIs resulted in several variants with greatly improved activity towards these chalcones. Furthermore, the preparative scale conversion catalyzed by bacterial CHIs has been performed for five chalcones and revealed (S)-selectivity with up to 96% ee, which provides an alternative biocatalytic route for the synthesis of (S)-flavanones in high yields.
Hannes Meinert, Dong Yi, Bastian Zirpel, Eva Schuiten, Torsten Geißler, Egon Gross, Stephan I Brückner, Beate Hartmann, Carsten Röttger, Jakob P Ley, Uwe Bornscheuer

1039 related Products with: Discovery of Novel Bacterial Chalcone Isomerases by a Sequence-Structure-Function-Evolution Strategy for Enzymatic Synthesis of (S)-Flavanones.

0.2 mg 100ul100 TESTS1 LITRE100 µg1 g 500 G200.00 ug1,000 tests1 KIT

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#34129218   2021/06/15 To Up

Astaxanthin Relieves Busulfan-Induced Oxidative Apoptosis in Cultured Human Spermatogonial Stem Cells by Activating the Nrf-2/HO-1 pathway.

Many child cancer patients endure anticancer therapy containing alkylating agents before sexual maturity. Busulfan (BU), as an alkylating agent, is a chemotherapy drug, causing DNA damage and cytotoxicity in germ cells. In the present study, we aimed to investigate the protective effect of astaxanthin (AST), as a potent antioxidant and powerful reactive oxygen species (ROS) scavenger, on BU-induced toxicity in human spermatogonial stem cells. For this purpose, testes were obtained from four brain-dead donors. After tissue enzymatic digestions, testicular cells were cultured for 3 weeks for spermatogonial stem cell (SSC) isolation and purification. K562 cell line was cultured to survey the effect of AST on cancer treatment. The cultured SSCs and K562 cell line were finally treated with AST (10μM), BU (0.1nM), and AST+BU. The expression of NRF-2, HO-1, SOD2, SOD3, TP53, and apoptotic genes, including CASP9, CASP3, BCL2, and BAX, were assayed using real-time PCR. Moreover, ROS level in different groups and malondialdehyde level and total antioxidant capacity in cell contraction of SSCs were measured using ELISA. Data showed that AST significantly upregulated the expression of NRF-2 gene (P<0.001) and protein (P<0.005) and also significantly decreased the production of BU-induced ROS (P<0.001). AST activated the NRF-2/HO-1 pathway that could remarkably restrain BU-induced apoptosis in SSCs. Interestingly, AST upregulated the expression level of apoptosis genes in the K562 cell line. The results of this study indicated that AST reduces the side effects of BU on SSCs without interference with its chemotherapy effect on cancerous cells through modulation of the NRF-2/HO-1 and mitochondria-mediated apoptosis pathways.
Azita Afzali, Fardin Amidi, Morteza Koruji, Hassan Nazari, Mohammad Ali Sadighi Gilani, Aligholi Sobhani Sanjbad

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100ul1 mg10 ug96 wells (1 kit)1.00 flask100μg2 Pieces/Box 100ul 100ul1x10e7 cells10ug4 Membranes/Box

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#34128568   2021/06/15 To Up

Selective 13C-labels on repeating glycan oligomers to reveal protein binding epitopes through NMR: polylactosamine binding to Galectins.

A combined chemo-enzymatic synthesis/NMR-based methodology is presented to identify, in unambiguous manner, the distinctive binding epitope within repeating sugar oligomers when binding to protein receptors. The concept is based on the incorporation of 13 C-labels at specific monosaccharide units, selected within a repeating glycan oligomeric structure. No new chemical tags are added, and thus the chemical entity remains the same, while the presence of the 13 C-labeled monosaccharide breaks the NMR chemical shift degeneracy that occurs in the non-labeled compound and allows the unique identification of the different components of the oligomer. The approach is demonstrated by a proof-of-concept study dealing with the interaction of a polylactosamine hexasaccharide with five different galectins that display distinct preferences for these entities.
Maria J Moure, Ana Gimeno, Sandra Delgado, Tammo Diercks, Geert-Jan Boons, Jesus Jimenez-Barbero, Ana Arda

2698 related Products with: Selective 13C-labels on repeating glycan oligomers to reveal protein binding epitopes through NMR: polylactosamine binding to Galectins.

100 UG96T5 x 200 ug100 200 1mg1 mg250ul100 μg 100ul0.2 mg

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