Abstract:
Thioredoxins are small proteins distinguished by the presence of a conserved dicysteine active site. In oxidized thioredoxin, the two cysteines form a disulfide bond that is targeted by the enzyme thioredoxin reductase. Together with an electron donor, thioredoxin and thioredoxin reductase form the 'thioredoxin system' that is present in all organisms. Thioredoxins participate in dithiol/disulfide exchange reactions with a large range of cellular substrates. Higher plants possess a very complex thioredoxin profile consisting of at least two different thioredoxin systems that contain distinct, multigenic thioredoxin classes which have different intracellular localizations. In this review we summarise the current state of knowledge regarding the function of plant thioredoxins representing all systems and classes.
Keywords: Key words: Thioredoxin; chloroplast enzyme; redox regulation; NADPH thioredoxin reductase; ferredoxin thioredoxin reductase; multigene family; disulfide; seed germination.
Footnotes
Received 30 October 2001; received after revision 13 December 2001; accepted 17 December 2001