title: Isolation, purification, and characterization of pregnancy-specific protein B from elk and moose placenta.
abstract: Pregnancy-specific protein B (PSPB) was isolated, purified, and partially characterized from elk and moose placenta. The procedure, which was monitored by bovine PSPB (bPSPB) RIA, included homogenization and extraction in aqueous solution, acidic and ammonium sulfate precipitation, and ion exchange, gel filtration, and affinity chromatographies. The estimated molecular sizes of moose PSPB (mPSPB) were 58 kDa and 31 kDa, and of elk PSPB (ePSPB) were 57 kDa, 45 kDa, and 31 kDa by SDS-PAGE. The isoelectric points of mPSPB were 4.8, 6.6, and 6.7, and of ePSPB were 4.8, 4.9, 6.1, and 6.2 as determined by isoelectric focusing and two-dimensional gel electrophoresis. The carbohydrate contents of mPSPB and ePSPB were approximately 3.15% and 4.98%, respectively. Although ePSPB and mPSPB were recognized by anti-bPSPB in an Ouchterlony double immunodiffusion test, they were found to share identical epitopes and partial identities compared to bPSPB. After treatment at different temperatures (20-60 degrees C) for 1 h, the immunoreactivities of ePSPB and mPSPB in serum were very stable. Only ePSPB in serum treated at 60 degrees C lost some immunoreactivity. After alteration of serum pH (pH 3-11) for 2 h, the immunoreactivities of ePSPB and mPSPB became lower at pH 3 and 4, and remained stable from pH 5 to 11. These data show that moose and elk PSPB have properties similar to those of bovine and ovine PSPB.
authors.affiliation: Department of Animal and Veterinary Science, University of Idaho, Moscow, Idaho 83844, USA.
authors.forename: F
authors.initials: F
authors.lastname: Huang
authors.forename: D C
authors.initials: DC
authors.lastname: Cockrell
authors.forename: T R
authors.initials: TR
authors.lastname: Stephenson
authors.forename: J H
authors.initials: JH
authors.lastname: Noyes
authors.forename: R G
authors.initials: RG
authors.lastname: Sasser
mesh_terms: D000818:Animals; D016282:Aspartic Acid Endopeptidases / Q000302:isolation & purification*; D002417:Cattle; D003670:Deer / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel / Q000662:veterinary; D005260:Female; D006023:Glycoproteins / Q000302:isolation & purification*; D006863:Hydrogen-Ion Concentration; D010920:Placenta / Q000737:chemistry*; D011257:Pregnancy Proteins / Q000302:isolation & purification*; D011863:Radioimmunoassay / Q000662:veterinary; D013696:Temperature
chemical_list: D006023:Glycoproteins; D011257:Pregnancy Proteins; D016282:Aspartic Acid Endopeptidases; C094766:pregnancy-associated glycoprotein 1