Figure 3.

SDS-PAGE of the Gly-POMC-His₆ protein purified by the Ni-affinity (a) and hydroxyapatite chromatography (b). (a) Lane 1, total cells; lanes 2 and 3, supernatants and precipitates after centrifugation of the sonicated cells, respectively; lanes 4 and 5, non-bound and washed fractions, respectively; lanes 6–11, fractions of 400 mM imidazole solutions. (b) Lanes 1–5, fractions of 200 mM sodium phosphate buffer (pH 6.0). M represents marker proteins. The Gly-POMC-His₆ protein are indicated by arrow heads.