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Purification and characterization of a second type thioredoxin peroxidase (type II TPx) from Saccharomyces cerevisiae.
Biochemistry. 1999 Jan 12; 38(2):776-83.B

Abstract

A yeast peroxidase that reduces H2O2 and alkyl hydroperoxides with the use of reducing equivalents provided by thioredoxin was identified previously and named thioredoxin peroxidase (TPx) [Chae, H. Z., Chung, S. J., and Rhee, S. G. (1994) J. Biol. Chem. 269, 27670-27678]. A second type thioredoxin-dependent peroxidase, named type II TPx, has now been purified from yeast, and several peptide sequences have been obtained. Using those sequences, the corresponding cDNA has been identified from the GenBank database. Comparison of the predicted sequence of 176 amino acids of type II TPx with that of the 195 residues of TPx, now renamed type I TPx, revealed no substantial homology except for a short segment preceding Cys62 of type II TPx. Kinetic characterization of the reactions catalyzed by type I and II TPxs revealed that type I preferentially reduces H2O2 rather than alkyl hydroperoxides, whereas type II shows the reverse specificity. Type II TPx contains three cysteine residues at positions 31, 62, and 120. Experiments with mutant proteins in which these three cysteine residues were replaced individually with serine suggest that Cys62-SH constitutes the site of oxidation by peroxides and that the oxidized Cys62 reacts with the Cys120-SH group of another type II TPx molecule to form an intermolecular disulfide linkage. The formed disulfide can then be reduced by thioredoxin, but not by glutathione. Thus, type II TPx mutants lacking Cys62 or Cys120 showed no detectable TPx activity, whereas mutation of Cys31 had no effect on TPx activity. An antioxidant function of type II TPx in intact cells was demonstrated by the observation that Escherichia coli cells overexpressing wild-type protein were less sensitive to inhibition of growth by alkyl hydroperoxides than were control cells or cells overexpressing the mutant protein lacking Cys62.

Authors+Show Affiliations

Department of Food and Nutrition, College of Home Economics, Chonnam National University, Kwang-Ju, Korea.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Comparative Study
Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

9888818

Citation

Jeong, J S., et al. "Purification and Characterization of a Second Type Thioredoxin Peroxidase (type II TPx) From Saccharomyces Cerevisiae." Biochemistry, vol. 38, no. 2, 1999, pp. 776-83.
Jeong JS, Kwon SJ, Kang SW, et al. Purification and characterization of a second type thioredoxin peroxidase (type II TPx) from Saccharomyces cerevisiae. Biochemistry. 1999;38(2):776-83.
Jeong, J. S., Kwon, S. J., Kang, S. W., Rhee, S. G., & Kim, K. (1999). Purification and characterization of a second type thioredoxin peroxidase (type II TPx) from Saccharomyces cerevisiae. Biochemistry, 38(2), 776-83.
Jeong JS, et al. Purification and Characterization of a Second Type Thioredoxin Peroxidase (type II TPx) From Saccharomyces Cerevisiae. Biochemistry. 1999 Jan 12;38(2):776-83. PubMed PMID: 9888818.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Purification and characterization of a second type thioredoxin peroxidase (type II TPx) from Saccharomyces cerevisiae. AU - Jeong,J S, AU - Kwon,S J, AU - Kang,S W, AU - Rhee,S G, AU - Kim,K, PY - 1999/1/15/pubmed PY - 1999/1/15/medline PY - 1999/1/15/entrez SP - 776 EP - 83 JF - Biochemistry JO - Biochemistry VL - 38 IS - 2 N2 - A yeast peroxidase that reduces H2O2 and alkyl hydroperoxides with the use of reducing equivalents provided by thioredoxin was identified previously and named thioredoxin peroxidase (TPx) [Chae, H. Z., Chung, S. J., and Rhee, S. G. (1994) J. Biol. Chem. 269, 27670-27678]. A second type thioredoxin-dependent peroxidase, named type II TPx, has now been purified from yeast, and several peptide sequences have been obtained. Using those sequences, the corresponding cDNA has been identified from the GenBank database. Comparison of the predicted sequence of 176 amino acids of type II TPx with that of the 195 residues of TPx, now renamed type I TPx, revealed no substantial homology except for a short segment preceding Cys62 of type II TPx. Kinetic characterization of the reactions catalyzed by type I and II TPxs revealed that type I preferentially reduces H2O2 rather than alkyl hydroperoxides, whereas type II shows the reverse specificity. Type II TPx contains three cysteine residues at positions 31, 62, and 120. Experiments with mutant proteins in which these three cysteine residues were replaced individually with serine suggest that Cys62-SH constitutes the site of oxidation by peroxides and that the oxidized Cys62 reacts with the Cys120-SH group of another type II TPx molecule to form an intermolecular disulfide linkage. The formed disulfide can then be reduced by thioredoxin, but not by glutathione. Thus, type II TPx mutants lacking Cys62 or Cys120 showed no detectable TPx activity, whereas mutation of Cys31 had no effect on TPx activity. An antioxidant function of type II TPx in intact cells was demonstrated by the observation that Escherichia coli cells overexpressing wild-type protein were less sensitive to inhibition of growth by alkyl hydroperoxides than were control cells or cells overexpressing the mutant protein lacking Cys62. SN - 0006-2960 UR - https://www.unboundmedicine.com/medline/citation/9888818/Purification_and_characterization_of_a_second_type_thioredoxin_peroxidase__type_II_TPx__from_Saccharomyces_cerevisiae_ L2 - https://doi.org/10.1021/bi9817818 DB - PRIME DP - Unbound Medicine ER -