Reprod. Nutr. Dev. 42 (2002) 227-241
DOI: 10.1051/rnd:2002021

Characterization of pregnancy-associated glycoproteins extracted from zebu (Bos indicus) placentas removed at different gestational periods

Noelita Melo Sousa^a, Benoit Remy^b, Bouchra El Amiri^b, José Ricardo De Figueiredo^a, Henri Banga-Mboko^b, Paulo Bayard Dias Gonçalves^a and Jean-François Beckers<sup>b

a</sup>  Faculty of Veterinary Medicine, Rural Sciences Center, Federal University of Santa Maria, RS 97105-900, Brazil
^b  Physiology of Reproduction, Faculty of Veterinary Medicine, University of Liege, 4000, Belgium

(Received 14 February 2002; accepted 21 May 2002)

Abstract
In the present work, two biochemical approaches were used to characterize PAGs isolated from Bos indicus fetal cotyledons removed at different gestational ages. The first procedure included acidic and ammonium sulfate precipitations, anion and cation exchange chromatographies and the second included pepstatin-agarose affinity chromatography. A bovine PAG radioimmunoassay was used to monitor the immunoreactivity throughout the isolation procedures. The most immunoreactive fractions issued from cation exchange and affinity chromatographies were analyzed by SDS-PAGE and Western blotting, before transfer to a polyvinylidene difluoride (PVDF) membrane for NH ₂-microsequence determination. Use SDS-PAGE and Western blotting, different isoforms of PAG with apparent molecular masses of 51 to 69 kDa and isoelectric points varying from 4.4 to 6.7 were identified in the placentas from different gestational ages. N-terminal microsequencing (10 to 25 aa long) indicates the expression of one single terminal amino acid sequence in the Bos indicus placenta, which is 100% identical to the bovine PAG-1.

Key words: pregnancy-associated glycoprotein / purification / zebu / placenta / N-terminal microsequencing

Correspondence and reprints: Jean-François Beckers
    e-mail: jfbeckers@ulg.ac.be

© INRA, EDP Sciences 2002