title: Reducing the heterogeneity of chemically conjugated targeted toxins: homogeneous basic FGF-saporin.
abstract: Basic fibroblast growth factor-saporin (FGF-SAP) is an extremely potent cytotoxic agent for cells bearing the FGF receptor. For its synthesis, the two free cysteines on the surface of basic FGF are available for linking by disulfide bridge to SAP which has been derivatized with a reactive sulfhydryl. Because of the heterogeneous nature of the synthesis, the resulting conjugate is heterogeneous as judged by gel electrophoresis. We have removed by site-directed mutagenesis one of the reactive cysteines of basic FGF and have purified monoderivatized SAP to use as the reactants. The resulting chemical conjugate shows a single band containing only 1 mol of basic FGF and 1 mol of SAP per molecule. This homogeneous conjugate is a potent cytocidal agent to cells bearing the FGF receptor.
authors.affiliation: Whittier Institute for Diabetes and Endocrinology, Department of Molecular and Cellular Growth Biology, La Jolla, California 92037.
authors.forename: D A
authors.initials: DA
authors.lastname: Lappi
authors.forename: R
authors.initials: R
authors.lastname: Matsunami
authors.forename: D
authors.initials: D
authors.lastname: Martineau
authors.forename: A
authors.initials: A
authors.lastname: Baird
mesh_terms: D016475:3T3 Cells; D000818:Animals; D001483:Base Sequence; D015153:Blotting, Western; D003545:Cysteine / Q000235:genetics; D005260:Female; D016222:Fibroblast Growth Factor 2 / Q000235:genetics* / Q000378:metabolism / Q000633:toxicity; D006801:Humans; D000922:Immunotoxins / Q000737:chemistry* / Q000633:toxicity*; D008546:Melanoma, Experimental / Q000188:drug therapy; D051379:Mice; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D009699:N-Glycosyl Hydrolases; D010051:Ovarian Neoplasms / Q000188:drug therapy; D010940:Plant Proteins / Q000302:isolation & purification* / Q000378:metabolism / Q000633:toxicity; D017468:Receptors, Fibroblast Growth Factor / Q000378:metabolism; D054789:Ribosome Inactivating Proteins, Type 1; D000076985:Saporins; D012694:Serine / Q000235:genetics; D014407:Tumor Cells, Cultured
chemical_list: D000922:Immunotoxins; D010940:Plant Proteins; D017468:Receptors, Fibroblast Growth Factor; D054789:Ribosome Inactivating Proteins, Type 1; D016222:Fibroblast Growth Factor 2; D012694:Serine; D009699:N-Glycosyl Hydrolases; D000076985:Saporins; D003545:Cysteine