Abstract
We characterized the relationship between γ-glutamylcysteine dipeptidyl transpeptidase in Schizosaccharomyces pombe and Cd ions. The transpeptidase activity increased in a Cd concentration ranging from 0 to 10 mM, whereas it decreased at concentrations above 300 mM. These results suggested that there are at least two Cd binding sites on the transpeptidase. The binding of Cd to the primary site, which has higher affinity for Cd ions, might activate the enzyme. The binding to the secondary site, which has lower affinity for Cd ions on the other hand, would be responsible for inactivation of the enzyme at higher levels of Cd.
