A and B SDS-PAGE purity and trypsin resistance gels for the H3 rHA proteins. A. Each rHA protein was loaded in duplicate to give 1 μg total protein per lane. The samples were separated using 4-12% gradient Nu-PAGE gels and stained with Coomassie Blue. Molecular weights of the proteins standards are shown. B. Shown are the reducing SDS-PAGE gels from the trypsin resistance assay. Each H3 rHA protein was analyzed neat (Lane 1), after trypsin treatment (Lane 2), after heat treatment (Lane 3), and after heat and trypsin treatment (Lane 4). The trypsin enzyme is loaded as a control and molecular weights of the protein standards are shown. HA1 and HA2 are indicated by arrows.