SODIUM DODECYL-SULFATE POLYACRYLAMIDE-GEL ELECTROPHORESIS OF RECOMBINANT HEPATITIS-B SURFACE-ANTIGEN PARTICLES

To investigate the factors leading to broadening of the recombinant he patitis B surface antigen (HBsAg) peak in size-exclusion chromatograph y, the HBsAg particles eluting in different regions of the peak were s ubjected here to electrophoretic analysis. In nonreduced samples, the 24-kD band corresponding to the S monomer was detected when excessivel y large amounts of HBsAg were loaded onto the gel. Hence, some monomer s are not disulfide-crosslinked in assembled particles. On the other h and, the results of alkylation experiments indicated the presence of f ree sulfhydryl group(s) in a little portion of freshly-purified HBsAg which was retarded on the size-exclusion chromatographic column and ha d significant antigenicity. This fraction of HBsAg was shown to be oli gomeric and capable of spontaneous assembly into higher-order structur es during aging. (C) 1998 Elsevier Science B.V.