Enzyme regulation by biological disulfides.

More than a dozen enzymes have been found to be activated or inhibited in vitro by disulfide-exchange between the protein and small-molecule disulfides. Accordingly, thiol/disulfide ratio changes in vivo may be of great importance in the regulation of cellular metabolism. An awareness of this regulatory mechanism in both host cells and parasites, coupled with information on the presence or absence of key enzymes, may lead to rational drug design against certain diseases involving thiol intermediates, including trypanosomiasis.