Ixodes scapularis:: Salivary kininase activity is a metallo dipeptidyl carboxypeptidase

Saliva and salivary gland homogenates of Ixodes scapularis contain a dipeptidyl carboxypeptidase activity that accounts for the previously described salivary kininase activity of this tick. Reversed phase HPLC and laser desorption mass spectrography of the reaction product!; identified bradykinin fragment 1-7 and 1-5 as being produced subsequent to incubation of purified salivary kininase with bradykinin. The activity was inhibited by captopril and EDTA and was activated by cobalt and manganese, a behavior similar to that displayed by angiotensin-converting enzymes of vertebrate and invertebrate origins. (C) 1998 Academic Press.