Cobalamin binding proteins in the human fetus.
Cobalamin binding proteins are synthesized by the fetus from at least 16-19 gestational weeks. Cerebrospinal fluid contained transcobalamin with size and isoelectric points identical to adult transcobalamin. The unsaturated cobalamin-binding capacity in the fetal cerebrospinal fluid was comparable to adult levels, that is 0.01-0.04 nmol/l, median 0.03 nmol/l, n = 4. The unsaturated cobalamin-binding capacity in serum was low compared to adult values (0.02-0.04 nmol/l, median 0.03 nmol/l, n = 4). The unsaturated cobalamin-binding capacity in at term umbilical cord serum was alike for arterial and venous blood. The values obtained was 0.14-1.03 nmol/l, median 0.66 nmol/l, n = 22, which was two thirds of the corresponding values in maternal serum: In the amniotic fluid haptocorrin, intrinsic factor and transcobalamin were identical with the adult binders regarding the size and the isoelectric point.
Department of Medicine and Haematology, Gentofte Hospital, University of Copenhagen, Denmark.
M
M
Hansen
C K
CK
Høgdall
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N
Kryger-Baggesen
D005333:Fetus / Q000502:physiology*; D006801:Humans; D007526:Isoelectric Point; D008970:Molecular Weight; D014155:Transcobalamins / Q000097:blood / Q000134:cerebrospinal fluid / Q000502:physiology*; D014805:Vitamin B 12 / Q000378:metabolism
D014155:Transcobalamins; D014805:Vitamin B 12