There is a commercial kit for thioredoxin reductase assay, detailed on http://www.abcam.com/thioredoxin-reductase-assay-kit-colorimetric-ab83463.html

Thanks Mr Liu . I have seen those and also the ones from sigma but my concern is the fact that what they all have is mammalian thioredoxin and i am looking at Bacterial thioredoxin and that is where i am worried about compatibility due to enzyme specificity. the closest i have seen is that of  E. coli. I am looking at the protocols for mammalian cells and am wondering if it will be suitable for bacterial cell. Thanks for your help

Chidi here is another link (but still based on mammalian cell lysate)

https://www.caymanchem.com/pdfs/10007892.pdf

I will suggest you contact any of these companies and ask them about the compatibility issue.

The cellular role and action of TrX reductase maybe similar in both mammalian and bacterial cells (again ask likes of Sigma, Cayman and Abcam)

If you have protocol and materials on E.coli, then that may be enough to go ahead since E.coli is a bacterium

Thanks Fagunwa I will just try with the e coli  Thioredoxin and see what it looks like.