Open AccessBiochemical characterization of thioredoxin 1 from Dictyostelium discoideum
Author(s) -
WETTERAUER Birgit,
VÉRON Michel,
MIGINIACMASLOW Myroslawa,
DECOTTIGNIES Paulette,
JACQUOT JeanPierre
Publication year - 1992
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1992.tb17331.x
Subject(s) - ferredoxin , dictyostelium discoideum , biochemistry , ferredoxin thioredoxin reductase , fructose 1,6 bisphosphatase , chloroplast , biology , reductase , malate dehydrogenase , dehydrogenase , thioredoxin , ferredoxin—nadp(+) reductase , thioredoxin reductase , fructose , enzyme , gene
Multiple genes for thioredoxins ( TRX ) have been demonstrated in Dictyostelium discoideum . We expressed the cDNA for one of these genes (DdTrxl) in E . coli and purified the protein to homogeneity. The interaction with classic substrates as well as TRX reductases was analysed. It reacted with every tested substrate: insulin, NADP‐dependent malate dehydrogenase and fructose‐1,6‐bisphosphatase. With a S 0.5 of 20 uM, the reactivity with the fructose‐1,6‐bisphosphatase is the highest ever found for a heterologous TRX. DdTRX1 itself is accepted as a substrate by the chloroplast ferredoxin‐dependent TRX reductase, as well as by the E. coli NADPH‐dependent TRX reductase. Thus, the Dictyostelium TRX is functionally promiscuous. Its reactivity with insulin, chloroplast NADP‐dependent malate dehydrogenase and ferredoxin‐dependent TRX reductase resemble those of other TRX. It is, however, clearly different in its good interaction with chloroplast fructose‐1,6‐bisphos‐phatase and in its poor interaction with E. coli NADP‐dependent TRX reductase.