Molecules of the family of aspartic proteinases in the placenta of ruminants: hormones or proteins?
Beckers, J.F.; Roberts, R.M.; Zoli, A.P.; Ectors, F.; Derivaux, J.
Bulletin et Memoires de l'Academie Royale de Medecine de Belgique 149(8-11) 355-364; Discussion: 364-367
1994
ISSN/ISBN: 0377-8231 PMID: 7550037 Document Number: 437071
The ruminant placenta contains binucleate trophoblastic cells synthesizing proteins, migrating cross the barrier and fusing with endothelial cells of the endometrium. Recently described were two glycoproteins from the family of aspartic proteases, apparently lacking the enzymatic activity: the pregnancy associated glycoproteins I and II (PAGI and PAGII). The first (PAGI) is largely secreted in maternal blood, this characteristic copes with the lack of proteolytic activity. The second (PAGII) is not completely characterized. However, it binds to lutropin (LH) receptors with high affinity. This binding allows to assume that PAGII is likely the same as the bovine chorionic gonadotropin identified earlier (bCG). A better characterization of these glycoproteins (PAGI and PAGII) and other members of the family (PAGIII...) will answer these questions together with the unexplained invasive process of the placenta.