High level of alpha1-acid glycoprotein in human seminal plasma is associated with high branching and expression of Lewis(a) groups on its glycans: supporting evidence for a prostatic origin.
BACKGROUND
Changes in concentration of seminal plasma alpha(1)-acid glycoprotein (AGP) have been studied in detail before. However, the source of high levels of AGP as well as the glycosylation of seminal plasma AGP has not been elucidated yet.


METHODS
The glycosylation of AGP was studied by crossed affinity immunoelectrophoresis using fucose-specific lectins and immunostaining. Glycan structure and monosaccharide analyses were performed by high pH anion exchange chromatography with pulsed amperometric detection. Fucosyltransferases were analyzed for activity and their substrate specificity was determined.


RESULTS
Two types of fucosylation were detected; Lewis(x) and Lewis(a). Lewis(a) groups were only present on AGP of individuals with a high concentration and were completely absent when the AGP concentration in seminal plasma was low. Lewis(a) expression coincides with a higher degree of branching of the glycans and a relative increased alpha4-fucosyltransferase activity. The molecular weight of all seminal plasma AGP was slightly higher than of blood plasma AGP (approx. 47 vs. 41-43 kDa).


CONCLUSIONS
The results indicate that AGP in seminal fluid most likely originates from the prostate and that it is either alpha3- or alpha4-fucosylated.
Poland
Dennis C W
DC
Glycoimmunology Group, Department of Molecular Cell Biology, VU Medical Center, Van der Boechorststraat, BT Amsterdam, The Netherlands.
Kratz
Ewa
E
Vermeiden
Jan P W
JP
De Groot
Steffen M
SM
Bruyneel
Ben
B
De Vries
Theodora
T
Van Dijk
Willem
W
D000581:Amidohydrolases / Q000378:metabolism; D002236:Carbohydrate Conformation; D005647:Fucosyltransferases / Q000378:metabolism; D006031:Glycosylation; D006801:Humans; D007123:Immunoelectrophoresis, Two-Dimensional; D037102:Lectins; D007983:Lewis Blood Group Antigens / Q000032:analysis / Q000737:chemistry; D008297:Male; D008970:Molecular Weight; D009005:Monosaccharides / Q000032:analysis; D009961:Orosomucoid / Q000032:analysis* / Q000737:chemistry; D043524:Peptide-N4-(N-acetyl-beta-glucosaminyl) Asparagine Amidase; D037121:Plant Lectins; D011134:Polysaccharides / Q000032:analysis / Q000378:metabolism; D011467:Prostate / Q000378:metabolism*; D012661:Semen / Q000737:chemistry* / Q000201:enzymology; D013379:Substrate Specificity
D037102:Lectins; D007983:Lewis Blood Group Antigens; D009005:Monosaccharides; D009961:Orosomucoid; D037121:Plant Lectins; D011134:Polysaccharides; C064549:lectin, Aleuria aurantia; C033619:lentil lectin; D005647:Fucosyltransferases; D000581:Amidohydrolases; D043524:Peptide-N4-(N-acetyl-beta-glucosaminyl) Asparagine Amidase