[A comparative evaluation of the level of sphingomyelinase activity in liver cell nuclei and in the brain].

It was discovered that there is sphingomyelinase activity in the rat liver nuclei. The maximum of enzyme activity is at pH 7.1. The data obtained demonstrated that the main part of sphingomyelinase is located in the nuclear membrane. Comparison of sphingomyelinase activity in cell nuclei, liver and brain homogenates shows high level of enzyme activity in the nuclei. The authors discuss possible participation of sphingomyelinases in changes of phospholipids composition in nuclear structure under different functional activity of cell nuclei.