The involvement of thioredoxin and thioredoxin reductase in the dimethyl sulphoxide reductase system of Saccharomyces cerevisiae

Dimethyl sulphoxide (DMSO) reductase activity in crude extracts of Saccharomyces cerevisiae NCYC240 was stimulated by addition of thioredoxin, but not by addition of thioredoxin reductase. The activity was partially purified. DEAE-cellulose could be used to separate thioredoxin and its reductase (which bound to the column) from the terminal DMSO-reductase protein (which failed to bind). The highly unstable purified terminal reductase so obtained required both thioredoxin and thioredoxin reductase to reconstitute activity with either dithiothreitol (DTT) or NADPH as electron donor. Partially purified terminal reductase had an Mr of about 15000.