Bettendorff L, Wins P, Schoffeniels E
Laboratory of General and Comparative Biochemistry, University of Liège, Belgium.
Biochem Biophys Res Commun. 1988 Aug 15;154(3):942-7. doi: 10.1016/0006-291x(88)90230-6.
Thiamine triphosphatase (TTPase) from membranes isolated from the main electric organ of E. electricus is activated about 8 fold by NO3-, I- and SCN- while SO42- is inhibitory. Activating anions shift the pH optimum of the enzyme from 5.0 to 8.0. The enzyme is irreversibly inactivated by low concentrations of 4,4'-diisothiocyano-2,2' disulfonic acid (DIDS), an inhibitor of anion transport. Anions protect from DIDS inactivation. These and other results suggest that the membrane-bound TTPase activity is tightly controlled, possibly through mechanisms involving anion transport.
