SDS/PAGE analysis of HeLa DNA-PK and recombinant Ku70/86. (A) 100 ng of Ku70/86 (lane b) and 100 ng of DNA-PKcs (lane c) purified from HeLa cell nuclear extract was resolved by 10% SDS/PAGE and analyzed by silver staining. Molecular mass markers (lane a) are as follows: Myosin (200 kDa), β-galactosidase (116 kDa), phosphorylase B (97.4 kDa), serum albumin (66.2 kDa), and ovalbumin (45.0 kDa). (B) Purified recombinant Ku70/86 (5 μg) (lane b) was resolved by 10% SDS/PAGE and analyzed by Coomassie blue staining. Molecular mass markers (lane a) are as follows: Myosin (200 kDa), β-galactosidase (116 kDa), phosphorylase B (97.4 kDa), serum albumin (66.2 kDa), ovalbumin (45.0 kDa), and carbonic anhydrase (31.0 kDa).