EFFECT OF PROSTAGLANDINS ON TYROSYLPROTEIN SULFOTRANSFERASE ACTIVITY RAT IN SUBMANDIBULAR SALIVARY-GLANDS

1. Tyrosylprotein sulfotransferase (TPST) is a key enzyme in the proce ssing of several secretory proteins, including those found in saliva. In this report, the effect of prostaglandins (PG) on TPST activity in submandibular salivary gland was investigated. 2. The results revealed that PGE(2) exhibited TPST stimulatory activity with a 1.5-fold stimu lation at 100 mu M concentration and a half maximal stimulation at 50 mu M. The PGE(2) stimulation was accompanied by an increase in the aff inity of TPST towards sulfate acceptor (Km 1.4 mu M-->0.12 mu M) with little change in V-max. 3. The TPST activity was also stimulated by tw o other major prostaglandins of salivary glands, PGF(2 alpha) and 6-Ke to-PGF(1 alpha), however to lesser extent, 22 and 23%, respectively. A rachidonic acid, an intermediate prostaglandin precursor, had no effec t on TPST activity. 4. The results suggest that prostaglandins and in particular PGE(2) may play a role in the regulation of TPST catalyzed secretory protein tyrosine sulfation in salivary glands.