Hepatitis B surface antigen assembles in a post-ER, pre-Golgi compartment

The immunoprecipitated proteins were analyzed by SDS-PAGE using 10-15% polyacrylamide gradient gels. After electrophoresis the gels were fixed with 10% (vol/vol) acetic acid and 50% (vol/vol) ethanol in H20 for 1 h at room temperature and processed for autoradiography using Entensify autoradiography enhancer (NEN Research, Boston, MA) according to the manufacturer's instructions. The gels were dried and exposed on Kodak X-OMAT AR film at -800C. The film was pre-exposed according to Laskey and Mills (1975) before autoradiography to obtain greater sensitivity and optimal linear response to the radioactivity on the gels. The exposed films were developed with Kodak RP X-OMAT Processor M6B.