Nuclei preparation buffer III

1.2 M sucrose

60 mM KCl

15 mM NaCl

5 mM MgCl₂

0.1 mM EGTA

15 mM Tris-HCl (pH 7.5)

0.5 mM DTT

0.1 mM PMSF

3.6 μg/ml aprotinin

Protease inhibitors, and in particular PMSF, are rather unstable in aqueous solutions. Therefore, PMSF, as well as DTT and aprotinin, should be added as late as possible, just before use.