Developmental changes in carbohydrate moiety of human alpha-fetoprotein.
Human AFP purified from fetal serum  and amniotic fluid was separated into three different variants by chromatography on concanavalin A insolubilized on Sepharose (Con A--Sepharose). The three variants were indistinguishable in immunodiffusion and radioimmunoassay. Sera from patients with yolk-sac tumor and amniotic fluid from early pregnancy were found to contain a high proportion (15-45%) of AFP which does not bind to Con A, while AFP in fetal and newborn sera, and in amniotic fluid from late pregnancy, contained less (2-6%) of this variant. The use of a large excess of Con A--Sepharose and the fact that the non-bound AFP consistently eluted as non-bound in rechromatography showed that this AFP is non-reactive with Con A. Fractionation of radiolabelled AFP from cord serum in a mixture with amniotic fluid verified the difference in the amount of the Con-A nonreactive variant in AFP from these two sources. These results suggest that AFP synthesized by the yolk-sac tissue and by the liver are glycosylated differently. The variant may prove to be diagnostically useful.
D000653:Amniotic Fluid / Q000032:analysis*; D002241:Carbohydrates / Q000032:analysis; D002846:Chromatography, Affinity; D003208:Concanavalin A; D005260:Female; D005312:Fetal Blood / Q000032:analysis*; D006801:Humans; D005779:Immunodiffusion; D007231:Infant, Newborn; D008099:Liver / Q000378:metabolism; D008113:Liver Neoplasms / Q000378:metabolism; D008649:Mesonephroma / Q000378:metabolism; D010051:Ovarian Neoplasms / Q000378:metabolism; D011247:Pregnancy; D011262:Pregnancy Trimester, Second; D011263:Pregnancy Trimester, Third; D011863:Radioimmunoassay; D013724:Teratoma / Q000378:metabolism; D000509:alpha-Fetoproteins / Q000032:analysis / Q000302:isolation & purification
D002241:Carbohydrates; D000509:alpha-Fetoproteins; D003208:Concanavalin A