Isopycnic centrifugation of rat-liver microsomes in isoosmotic gradients of Percoll and release of microsomal material by low concentrations of sodium deoxycholate.

Rat-liver microsomes were subjected to isopycnic centrifugation under isoosmotic conditions in gradients of Percoll containing 0%, 0.05%, 0.1% and 0.2% sodium deoxycholate, respectively. The buoyant density of the microsomes was in the range 1.043 to 1.046 g/ml, independent of the detergent concentration. Absorbance measurements and polyacrylamide gel electrophoresis revealed that the detergent causes an increase in the release of material from the microsomes. Electron microscopy studies showed that membrane disassembly was avoided if the microsomes were isolated at concentrations below 0.1% sodium deoxycholate.