<p>(A) 2-D gel electrophoresis of placental extract (100x). Positions of Mw markers are indicated. (B) Gelatin zymography in the second dimension. The activity corresponded to spot number 3 of A. (C) Immunological cross-reactivity between anti-sera of ubiquitin and (a) ubiquitin, (b) peptide fraction and (c) ovalbumin. (D) Immunological cross-reactivity between anti-sera of peptide fraction and (a) collagenase, (b) peptide fraction and (c) ovalbumin. (E) Gelatin zymography. Lane 1, ubiquitin (bovine); and Lane 2, peptide fraction. The arrow indicates the faint band of ubiquitin which roughly corresponds to that of placental ubiquitin. (F) Silver stained SDS-PAGE of ubiquitin (bovine, lane 1) and peptide fraction (lane 2). Approximate Mw of ubiquitin bands have been indicated.</p
