title: Preparation and characterization of a C-terminal fragment of pregnancy zone protein corresponding to the receptor-binding peptide from human alpha 2-macroglobulin.
abstract: Digestion of the pregnancy zone protein with papain at pH 4.5 yields an 18 kDa C-terminal fragment. This fragment consists of the 145 C-terminal amino-acid residues cleaved at Asn-1288 Ile and is homologous to the C-terminal receptor binding fragment of human alpha 2-macroglobulin obtained by cleavage with papain. The fragment contains an intrachain disulfide bond between 1308Cys and 1423Cys corresponding to that between 1304Cys and 1419Cys in alpha 2-macroglobulin. An oligosaccharide chain, is present in the C-terminal fragment of pregnancy zone protein as in human alpha 2-macroglobulin. The PZP C-terminal fragment was demonstrated to bind to the LRP/alpha 2M-receptor. Both the pregnancy zone protein and alpha 2-macroglobulin fragments bind three mAb's (alpha 1:1, R35, and 7H11D6) generated against alpha 2-macroglobulin. The mAb 7H11D6 was generated against the alpha 2-macroglobulin-proteinase complex (Isaacs, I.J., Steiner, J.P., Roche, P.A., Pizzo, S.V. and Strickland, D.K. (1988) J. Biol. Chem. 263, 6709-6714) and the binding of this to the C-terminal fragments of both pregnancy zone protein and alpha 2-macroglobulin indicates that both proteins use the same receptor recognition site for binding to the LRP/alpha 2M-receptor.
authors.affiliation: Department of Immunology, University of Umeå, Sweden.
authors.forename: P E
authors.initials: PE
authors.lastname: Jensen
authors.forename: L F
authors.initials: LF
authors.lastname: Arbelaez
authors.forename: V P
authors.initials: VP
authors.lastname: Shanbhag
authors.forename: T
authors.initials: T
authors.lastname: Stigbrand
mesh_terms: D000595:Amino Acid Sequence; D000911:Antibodies, Monoclonal / Q000276:immunology; D001665:Binding Sites; D002850:Chromatography, Gel; D004220:Disulfides / Q000737:chemistry; D004591:Electrophoresis, Polyacrylamide Gel; D004797:Enzyme-Linked Immunosorbent Assay; D006031:Glycosylation; D006801:Humans; D015151:Immunoblotting; D026503:Low Density Lipoprotein Receptor-Related Protein-1; D008969:Molecular Sequence Data; D010206:Papain / Q000378:metabolism; D010446:Peptide Fragments / Q000737:chemistry* / Q000378:metabolism*; D011257:Pregnancy Proteins / Q000737:chemistry / Q000378:metabolism*; D011485:Protein Binding; D011971:Receptors, Immunologic / Q000378:metabolism*; D011973:Receptors, LDL / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D000511:alpha-Macroglobulins / Q000737:chemistry* / Q000276:immunology / Q000378:metabolism
chemical_list: D000911:Antibodies, Monoclonal; D004220:Disulfides; D026503:Low Density Lipoprotein Receptor-Related Protein-1; D010446:Peptide Fragments; D011257:Pregnancy Proteins; D011971:Receptors, Immunologic; D011973:Receptors, LDL; D000511:alpha-Macroglobulins; D010206:Papain