Neutral surface aminopeptidase activity of human tumor cell lines

Abstract

Seven human tumor cell lines were studied for their neutral surface aminopeptidase (AP) activity. The activity was shown to exist on all cell lines to varying degrees. The neutral AP activity of the cell lines had similar Km values and were affected by the same inhibitors as those reported for AP's of peripheral blood lymphocytes (PBL, Refs. 1 and 2). However, a difference was seen in the Vmax values of the various cell lines. These values were shown to correlate (r = 0.767, P less than 0.05) with cell surface area.