Thioredoxin and thioredoxin reductase in pancreatic islets may participate in diabetogenic free-radical production
Grankvist, K.; Holmgren, A.; Luthman, M.; Täljedal, I.B.
Biochemical and Biophysical Research Communications 107(4): 1412-1418
1982
ISSN/ISBN: 0006-291X PMID: 6753843 Document Number: 190284
Mouse pancreatic islets rich in .beta.-cells contain .apprx. 42 pmol of thioredoxin and 1.8 pmol of thioredoxin reductase/mg islet protein, corresponding to a nominal concentration in the cell water of .apprx. 28 and 1.2 .mu.M. When mixed with alloxan, FeSO4 and NADPH in a cell-free system, thioredoxin (3.4 .mu.M) and thioredoxin reductase (0.2 .mu.M) purified from Escherichia coli induced a production of oxy-radicals as evidenced by the emission of light from luminol. Mammalian thioredoxin reductase from calf thymus (0.2 .mu.M) was capable of eliciting luminescence even in the absence of thioredoxin. The thioredoxin/thioredoxin reductase system may play important roles in the physiology and pathology of pancreatic .beta.-cells.