Thioredoxin system product line

The thioredoxin superfamily includes a growing number of proteins all having the same basic folding as thioredoxin and glutaredoxin with the active site -CXXC- located at the
C-terminal end of a beta-strand and followed by an alpha-helix. Thioredoxin is reduced to the dithiol form by NADPH and thioredoxin reductase (together called the thioredoxin system).

Most organisms have a thioredoxin system and many organisms have several isoforms of thioredoxin or thioredoxin reductase.

IMCO has several products of use in research on thioredoxin systems.

The mammalian thioredoxins are fully active with other mammalian thioredoxin reductases so recombinant human thioredoxin works with TR1 from rat.
The E.coli production of recombinant rat thioredoxin reductase which is a selenoprotein with the actice site –GCUG where U is selenocysteine and present as the penultimate amino acid results in 30 % read through of the ATG stop codon and 70 percent truncated enzyme. This is because the coding region for rat TrxR is inserted in a reading frame for formate dehydrogenase, which is an E.coli selenoprotein. The mammalian rat TR1 gene expressed directly in E.coli will generate 100 % truncated enzyme since the mechanism of E.coli selenoprotein synthesis and that of mammalian cells is different and the SECIS element in E.c oli selenoproteins follows directly after the ATG codon whereas in mammalian cells it is located in the 3`-untranslated region. The truncated TR enzyme is inactive. The enzyme preparation shows one band on SDS gels.