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Evidence for the co‐existence of glutathione reductase and trypanothione reductase in the non‐trypanosomatid Euglenozoa: Euglena gracilis Z
Author(s) -
Montrichard Françoise,
Le Guen Fabienne,
Laval-Martin Danielle L,
Davioud-Charvet Elisabeth
Publication year - 1999
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(98)01606-8
Subject(s) - glutaredoxin , thioredoxin reductase , euglena gracilis , glutathione reductase , biochemistry , dtnb , reductase , glutathione disulfide , glutathione , ferredoxin thioredoxin reductase , chemistry , escherichia coli , enzyme , biology , stereochemistry , chloroplast , glutathione peroxidase , gene
Two NADPH‐dependent disulfide reductases, glutathione reductase and trypanothione reductase, were shown to be present in Euglena gracilis , purified to homogeneity and characterized. The glutathione reductase ( M r 50 kDa) displays a high specificity towards glutathione disulfide with a K M of 54 μM. The amino acid sequences of two peptides derived from the trypanothione reductase ( M r 54 kDa) show a high level of identity (81% and 64%) with sequences of trypanothione reductases from trypanosomatids. The trypanothione reductase is able to efficiently reduce trypanothione disulfide ( K M 30.5 μM) and glutathionylspermidine disulfide ( K M 90.6 μM) but not glutathione disulfide, nor Escherichia coli thioredoxin disulfide, nor 5,5′‐dithiobis(2‐nitrobenzoate) (DTNB). These results demonstrate for the first time (i) the existence of trypanothione reductase in a non‐trypanosomatid organism and (ii) the co‐existence of trypanothione reductase and glutathione reductase in E. gracilis .