Hendriks D, De Meester I, Umiel T, Vanhoof G, van Sande M, Scharpé S, Yaron A
Department of Biophysics, Weizmann Institute of Science, Rehovot, Israel.
Clin Chim Acta. 1991 Feb 15;196(2-3):87-96. doi: 10.1016/0009-8981(91)90061-g.
Human white blood cells were shown to contain high aminopeptidase P activity. The specific activities found in the high-speed supernatant of the extracts of granulocytes, lymphocytes and monocytes ranged from 30 to 70 units per mg protein. Culturing lymphocytes during 7 days in the presence of phytohaemagglutinin resulted in a 70-200% increase in the specific aminopeptidase P activity and a 200% increase in the specific activity of dipeptidyl peptidase IV. The time-course of the activity of both aminopeptidase P and dipeptidyl peptidase IV during the stimulation of human T-lymphocytes by phytohaemagglutinin indicates an involvement of these two enzymes in the proliferative process of these immunocompetent cells. Due to their substrate specificity their potential substrates must have the N-terminal Xaa-Pro sequence known to be present in several immunologically important polypeptides.
