A cholecystokinin (CCK)-inactivating peptidase was purified and identi
fied as a membrane-bound isoform of tripeptidyl peptidase II (EC 3.4.
14. 10), a cytosolic subtilisin-like peptidase of previously unknown f
unctions. The peptidase was found in neurons responding to cholecystok
inin, as well as in non-neuronal cells. Butabindide, a potent and spec
ific inhibitor, was designed and shown to protect endogenous cholecyst
okinin from inactivation and to display pro-satiating effects mediated
by the CCKA receptor.