High Phospholipase Activities in Amoebae of Dictyostelium discoideum

Abstract

Amoebae of the cellular slime mold Dictyostelium discoideum exhibit high activities of particlebound phospholipase A and lysophospholipase. The activity of phospholipase A in homogenates of Dictyostelium cells was found to be 3,8 nmoles × mg protein−1× min−1 and of lysophospholipase 186 nmoles × mg protein−1× min−1. p‐Chloromercuribenzoate (pCMB) and digitonin were found to be inhibitors of phospholipase A while these compounds did not influence the activity of the lysophospholipase. There was no indication that homogenates of Dictyostelium contain phospholipase C activity. The lysolecithin‐acylating activity could only be detected in cell suspensions which were diluted before homogenisation to 2 mg protein/ml (2 × 107 cells/ml) probably because of the action of proteases or phospholipases in more concentrated homogenates. The results are discussed in view of the membrane activies of Dictyostelium amoebae during various morphogenetic stages. Copyright © 1970, Wiley Blackwell. All rights reserved