The phospholipase B of liver

Abstract

The presence of an active phospholipase B was demonstrated in glycerinated extracts of acetone-dried rat and sheep liver, with lysolecithin as a substrate. The liver extracts can also break down lysophosphatidylethanolamine when this is added in a soluble form. Maximal hydrolysis of lysolecithin was obtained at pH 6.2 and a substrate concentration between 2 and 3.5 x 10-3 [image]. The enzyme is resistant to most enzyme inhibitors. However, Hg2+, Cu2+ and Zn2+ ions are inhibitory, as is saturation of the incubation medium with ether. Lysolecithin breakdown was also observed with extracts from acetone-dried rat kidney, brain, heart, spleen and whole blood, but not with skeletal muscle. Phospholipase B is also present in sheep kidney and thyroid.