A Thioredoxin-Mediated Activation of Glutamine Synthetase and Glutamate Synthase in Synchronous Chlorella sorokiniana

Open Access
Publisher Website
Google Scholar
Abstract
The effects of thioredoxin, dithioerythrol, and mixtures of both on enzymes involved in N metabolism of Chlorella sorokiniana have been studied. Glutamine synthetase, inactivated in vivo, was activated 8-fold by thioredoxin and dithioerythrol. By the same treatment, the activity of glutamate synthase was stimulated nearly 4-fold. Thus, two key enzymes of N metabolism were shown to be regulated via thioredoxin. The enzymes of the nitrate reducing system, i.e. nitrate reductase and nitrite reductase, were not affected by thiols. From these results, a model of NO3− metabolism is put forward which considers the regulating effect of light.