Alkaline phosphatase activity of polymorphonuclear leucocytes and lymphocytes separated from normal human blood.

Suspensions of polymorphonuclear leucocytes and lymphocytes were prepared from normal human blood by the glass bead column method of Rabinowitz (1964). The alkaline phosphatase activity of the separated cells was determined by biochemical and cytochemical techniques. Lymphocytes were found to contain an enzyme catalysing the hydrolysis of beta-glycerophosphate at alkaline pH but not of p-nitrophenylphosphate at the same pH and in the same buffer system. The alkaline phosphatase in polymorphonuclear leucocytes catalysed the hydrolysis of both substrates equally. The importance of this finding to the interpretation of clinical data is discussed.