Mitochondrial Thioredoxin-Glutathione Reductase from Larval Taenia crassiceps (Cysticerci)
Mitochondrial thioredoxin-glutathione reductase was purified from larval Taenia crassiceps (cysticerci). The preparation showed NADPH-dependent reductase activity with either thioredoxin or GSSG, and was able to perform thiol/disulfide exchange reactions. At 25∘C specific activities were 437 ± 27...
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| Format: | Article |
| Language: | English |
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Wiley
2010-01-01
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| Series: | Journal of Parasitology Research |
| Online Access: | http://dx.doi.org/10.1155/2010/719856 |
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| author | Alberto Guevara-Flores Irene P. del Arenal Guillermo Mendoza-Hernández Juan Pablo Pardo Oscar Flores-Herrera Juan L. Rendón |
| author_facet | Alberto Guevara-Flores Irene P. del Arenal Guillermo Mendoza-Hernández Juan Pablo Pardo Oscar Flores-Herrera Juan L. Rendón |
| author_sort | Alberto Guevara-Flores |
| collection | DOAJ |
| description | Mitochondrial thioredoxin-glutathione reductase was purified from larval Taenia crassiceps (cysticerci). The preparation showed NADPH-dependent reductase activity with either thioredoxin or GSSG, and was able to perform thiol/disulfide exchange reactions. At 25∘C specific activities were 437 ± 27 mU mg-1 and 840 ± 49 mU mg-1 with thioredoxin and GSSG, respectively. Apparent Km values were 0.87 ± 0.04 μM, 41 ± 6 μM and 19 ± 10 μM for thioredoxin, GSSG and NADPH, respectively. Thioredoxin from eukaryotic sources was accepted as substrate. The enzyme reduced H2O2 in a NADPH-dependent manner, although with low catalytic efficiency. In the presence of thioredoxin, mitochondrial TGR showed a thioredoxin peroxidase-like activity. All disulfide reductase activities were inhibited by auranofin, suggesting mTGR is dependent on selenocysteine. The reductase activity with GSSG showed a higher dependence on temperature as compared with the DTNB reductase activity. The variation of the GSSG- and DTNB reductase activities on pH was dependent on the disulfide substrate. Like the cytosolic isoform, mTGR showed a hysteretic kinetic behavior at moderate or high GSSG concentrations, but it was less sensitive to calcium. The enzyme was able to protect glutamine synthetase from oxidative inactivation, suggesting that mTGR is competent to contend with oxidative stress. |
| format | Article |
| id | doaj-art-472378d24ed8463dafdb1b370538d75e |
| institution | Kabale University |
| issn | 2090-0023 2090-0031 |
| language | English |
| publishDate | 2010-01-01 |
| publisher | Wiley |
| record_format | Article |
| series | Journal of Parasitology Research |
| spelling | doaj-art-472378d24ed8463dafdb1b370538d75e2025-02-03T05:48:15ZengWileyJournal of Parasitology Research2090-00232090-00312010-01-01201010.1155/2010/719856719856Mitochondrial Thioredoxin-Glutathione Reductase from Larval Taenia crassiceps (Cysticerci)Alberto Guevara-Flores0Irene P. del Arenal1Guillermo Mendoza-Hernández2Juan Pablo Pardo3Oscar Flores-Herrera4Juan L. Rendón5Departamento de Bioquímica, Facultad de Medicina, Universidad Nacional Autónoma de México, Apartado Postal no. 70-159, 04510 México, DF, MexicoDepartamento de Bioquímica, Facultad de Medicina, Universidad Nacional Autónoma de México, Apartado Postal no. 70-159, 04510 México, DF, MexicoDepartamento de Bioquímica, Facultad de Medicina, Universidad Nacional Autónoma de México, Apartado Postal no. 70-159, 04510 México, DF, MexicoDepartamento de Bioquímica, Facultad de Medicina, Universidad Nacional Autónoma de México, Apartado Postal no. 70-159, 04510 México, DF, MexicoDepartamento de Bioquímica, Facultad de Medicina, Universidad Nacional Autónoma de México, Apartado Postal no. 70-159, 04510 México, DF, MexicoDepartamento de Bioquímica, Facultad de Medicina, Universidad Nacional Autónoma de México, Apartado Postal no. 70-159, 04510 México, DF, MexicoMitochondrial thioredoxin-glutathione reductase was purified from larval Taenia crassiceps (cysticerci). The preparation showed NADPH-dependent reductase activity with either thioredoxin or GSSG, and was able to perform thiol/disulfide exchange reactions. At 25∘C specific activities were 437 ± 27 mU mg-1 and 840 ± 49 mU mg-1 with thioredoxin and GSSG, respectively. Apparent Km values were 0.87 ± 0.04 μM, 41 ± 6 μM and 19 ± 10 μM for thioredoxin, GSSG and NADPH, respectively. Thioredoxin from eukaryotic sources was accepted as substrate. The enzyme reduced H2O2 in a NADPH-dependent manner, although with low catalytic efficiency. In the presence of thioredoxin, mitochondrial TGR showed a thioredoxin peroxidase-like activity. All disulfide reductase activities were inhibited by auranofin, suggesting mTGR is dependent on selenocysteine. The reductase activity with GSSG showed a higher dependence on temperature as compared with the DTNB reductase activity. The variation of the GSSG- and DTNB reductase activities on pH was dependent on the disulfide substrate. Like the cytosolic isoform, mTGR showed a hysteretic kinetic behavior at moderate or high GSSG concentrations, but it was less sensitive to calcium. The enzyme was able to protect glutamine synthetase from oxidative inactivation, suggesting that mTGR is competent to contend with oxidative stress.http://dx.doi.org/10.1155/2010/719856 |
| spellingShingle | Alberto Guevara-Flores Irene P. del Arenal Guillermo Mendoza-Hernández Juan Pablo Pardo Oscar Flores-Herrera Juan L. Rendón Mitochondrial Thioredoxin-Glutathione Reductase from Larval Taenia crassiceps (Cysticerci) Journal of Parasitology Research |
| title | Mitochondrial Thioredoxin-Glutathione Reductase from Larval Taenia crassiceps (Cysticerci) |
| title_full | Mitochondrial Thioredoxin-Glutathione Reductase from Larval Taenia crassiceps (Cysticerci) |
| title_fullStr | Mitochondrial Thioredoxin-Glutathione Reductase from Larval Taenia crassiceps (Cysticerci) |
| title_full_unstemmed | Mitochondrial Thioredoxin-Glutathione Reductase from Larval Taenia crassiceps (Cysticerci) |
| title_short | Mitochondrial Thioredoxin-Glutathione Reductase from Larval Taenia crassiceps (Cysticerci) |
| title_sort | mitochondrial thioredoxin glutathione reductase from larval taenia crassiceps cysticerci |
| url | http://dx.doi.org/10.1155/2010/719856 |
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