The isolation of nuclear membrane from a large-scale preparation of bovine liver nuclei

1. 1. A procedure for the large-scale preparation of bovine liver nuclei is described. 2. 2. Nuclear membrane was prepared by treatment of nuclei with deoxyribonuclease followed by extraction with a 0.5 M MgCl₂ solution. 3. 3. An evaluation of mitochondrial and microsomal contamination involving chemical, enzymatic and ultrastructural analysis indicated only slight contamination in both nuclear and nuclear membrane fractions. 4. 4. The total contaminating protein averaged 2.65% for nuclei and 10.6% for nuclear membrane. 5. 5. Electron microscopy showed that the membrane fraction contained both outer and inner nuclear membranes. 6. 6. The nuclear membrane fraction contained 74.6% protein, 8.9% RNA, 0.92% DNA, and 13.7% phospholipid. Recovery studies showed an average of 10.3% of the nuclear protein, 23.9% of the nuclear RNA, 0.27% of the nuclear DNA, and 47.1% of the nuclear phospholipid recovered in the membrane fraction.