scholarly journals Engineering Glutathione Transferase to a Novel Glutathione Peroxidase Mimic With High Catalytic Efficiency

2005 ◽  
Vol 280 (12) ◽  
pp. 11930-11935 ◽  
Author(s):  
Hui-jun Yu ◽  
Jun-qiu Liu ◽  
August Böck ◽  
Jing Li ◽  
Gui-min Luo ◽  
...  
Keyword(s):  
Glutathione Peroxidase ◽  
Glutathione Transferase ◽  
Catalytic Efficiency ◽  
Peroxidase Mimic

scholarly journals Xenopus gpx3 Mediates Posterior Development by Regulating Cell Death during Embryogenesis

Antioxidants ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 1265
Author(s):  
Hongchan Lee ◽  
Tayaba Ismail ◽  
Youni Kim ◽  
Shinhyeok Chae ◽  
Hong-Yeoul Ryu ◽  
...  
Keyword(s):  
Cell Death ◽  
Embryonic Development ◽  
Glutathione Peroxidase ◽  
Critical Role ◽  
Model Organism ◽  
Bmp Signaling ◽  
Terminal Deoxynucleotidyl Transferase ◽  
Peroxidase Mimic ◽  
Tail Region ◽  
Stage Of Development

Glutathione peroxidase 3 (GPx3) belongs to the glutathione peroxidase family of selenoproteins and is a key antioxidant enzyme in multicellular organisms against oxidative damage. Downregulation of GPx3 affects tumor progression and metastasis and is associated with liver and heart disease. However, the physiological significance of GPx3 in vertebrate embryonic development remains poorly understood. The current study aimed to investigate the functional roles of gpx3 during embryogenesis. To this end, we determined gpx3’s spatiotemporal expression using Xenopus laevis as a model organism. Using reverse transcription polymerase chain reaction (RT-PCR), we demonstrated the zygotic nature of this gene. Interestingly, the expression of gpx3 enhanced during the tailbud stage of development, and whole mount in situ hybridization (WISH) analysis revealed gpx3 localization in prospective tail region of developing embryo. gpx3 knockdown using antisense morpholino oligonucleotides (MOs) resulted in short post-anal tails, and these malformed tails were significantly rescued by glutathione peroxidase mimic ebselen. The gene expression analysis indicated that gpx3 knockdown significantly altered the expression of genes associated with Wnt, Notch, and bone morphogenetic protein (BMP) signaling pathways involved in tailbud development. Moreover, RNA sequencing identified that gpx3 plays a role in regulation of cell death in the developing embryo. Terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) and phospho-histone 3 (PH3) staining confirmed the association of gpx3 knockdown with increased cell death and decreased cell proliferation in tail region of developing embryos, establishing the involvement of gpx3 in tailbud development by regulating the cell death. Furthermore, these findings are inter-related with increased reactive oxygen species (ROS) levels in gpx3 knockdown embryos, as measured by using a redox-sensitive fluorescent probe HyPer. Taken together, our results suggest that gpx3 plays a critical role in posterior embryonic development by regulating cell death and proliferation during vertebrate embryogenesis.

scholarly journals Synthesis of alpha‐methyl selenocysteine and its utilization as a glutathione peroxidase mimic

2019 ◽  
Vol 25 (6) ◽  
pp. e3173 ◽  
Author(s):  
Robert J. Wehrle ◽  
Emma J. Ste.Marie ◽  
Robert J. Hondal ◽  
Douglas S. Masterson
Keyword(s):  
Glutathione Peroxidase ◽  
Peroxidase Mimic

Peroxidase Mimic Activities of Copper Selenide (CuSe) Nanoplates for Sensing H2O2 and L-Cysteine

2020 ◽  
Vol 20 (9) ◽  
pp. 5369-5375
Author(s):  
Bai Maojuan ◽  
Xu Chengcheng ◽  
Huang Xuanye ◽  
Liu Yanan ◽  
Wan Jun
Keyword(s):  
Electron Microscopy ◽  
Detection Limit ◽  
Energy Dispersive Spectrometer ◽  
Catalytic Efficiency ◽  
Relative Standard Error ◽  
Colorimetric Determination ◽  
Peroxidase Mimic ◽  
Biomedical Analysis ◽  
X Ray ◽  
Relative Standard

Compared with natural enzymes, artificial mimic enzymes have been widely studied for their high stability and cost effectiveness. In this study, CuSe nanoplates as a simulated enzyme which does not contain precious metals, has peroxidase activity. CuSe nanoplates were prepared and characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray energy dispersive spectrometer (EDS). Kinetic studies show that CuSe nanoplates exhibits a higher affinity for 3,3′,5,5′-teramethylbenzidine (TMB) than horseradish peroxidase (HRP). The rapid colorimetric determination of H2O2 and L-cysteine were developed based on the catalytic efficiency. The linear range of detection for H2O2 is 5.0×10−6~8.0×10−5 M, and the detection limit is 2.9×10−6 M, while the relative standard error is less than 5%. In addition, L-cysteine was detected with a detection limit of 0.2×10−6 M. The good selectivity of the determination to H2O2 and L-cysteine in aqueous solution was also achieved. CuSe nanoplates as a simulated enzyme for sensor applications would be used in environmental monitoring and biomedical analysis.

Modeling the Mechanism of the Glutathione Peroxidase Mimic Ebselen

2011 ◽  
Vol 50 (23) ◽  
pp. 12075-12084 ◽  
Author(s):  
Sonia Antony ◽  
Craig A. Bayse
Keyword(s):  
Glutathione Peroxidase ◽  
Peroxidase Mimic

scholarly journals The Role of Glutathione in the Isomerization of Δ5-Androstene- 3,17-dione Catalyzed by Human Glutathione Transferase A1-1

2001 ◽  
Vol 276 (15) ◽  
pp. 11698-11704 ◽  
Author(s):  
Pär L. Pettersson ◽  
Bengt Mannervik
Keyword(s):  
Active Site ◽  
Active Sites ◽  
Catalytic Mechanism ◽  
Glutathione Transferase ◽  
Ph Dependence ◽  
Enzymatic Catalysis ◽  
Catalytic Efficiency ◽  
Protonated Form ◽  
Hydroxyl Group ◽  
Isomerization Reaction

Human glutathione transferase (GST) A1-1 efficiently catalyzes the isomerization of Δ5-androstene-3,17-dione (AD) into Δ4-androstene-3,17-dione. High activity requires glutathione, but enzymatic catalysis occurs also in the absence of this cofactor. Glutathione alone shows a limited catalytic effect.S-Alkylglutathione derivatives do not promote the reaction, and the pH dependence of the isomerization indicates that the glutathione thiolate serves as a base in the catalytic mechanism. Mutation of the active-site Tyr9into Phe significantly decreases the steady-state kinetic parameters, alters their pH dependence, and increases the pKavalue of the enzyme-bound glutathione thiol. Thus, Tyr9promotes the reaction via its phenolic hydroxyl group in protonated form. GST A2-2 has a catalytic efficiency with AD 100-fold lower than the homologous GST A1-1. Another Alpha class enzyme, GST A4-4, is 1000-fold less active than GST A1-1. The Y9F mutant of GST A1-1 is more efficient than GST A2-2 and GST A4-4, both having a glutathione cofactor and an active-site Tyr9residue. The active sites of GST A2-2 and GST A1-1 differ by only four amino acid residues, suggesting that proper orientation of AD in relation to the thiolate of glutathione is crucial for high catalytic efficiency in the isomerization reaction. The GST A1-1-catalyzed steroid isomerization provides a complement to the previously described isomerase activity of 3β-hydroxysteroid dehydrogenase.

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