Small Molecular Weight Vitamin B12 Binders in Normal Human Serum

Nature ◽  
1968 ◽  
Vol 217 (5125) ◽  
pp. 272-274 ◽  
Author(s):  
EVANGELOS GIZIS ◽  
LEO M. MEYER
Keyword(s):  
Molecular Weight ◽  
Vitamin B12 ◽  
Human Serum ◽  
Normal Human Serum ◽  
Small Molecular Weight ◽  
Normal Human

State of iron(III) in normal human serum: low molecular weight and protein ligands besides transferrin

1970 ◽  
Vol 48 (12) ◽  
pp. 1339-1350 ◽  
Author(s):  
Bibudhendra Sarkar
Keyword(s):  
Molecular Weight ◽  
Human Serum ◽  
Binding Capacity ◽  
Normal Serum ◽  
Normal Human Serum ◽  
Void Volume ◽  
Antibody Concentration ◽  
Low Molecular Weight ◽  
Protein Ligands ◽  
Normal Human

A fraction of Fe(III) in normal human serum is bound to both low molecular weight as well as protein ligands besides transferrin. Citrate was shown to be the major Fe(III)-binding substance in the low molecular weight fraction. Amino acids, sugars, and organic acids, such as ascorbate, pyruvate, and lactate, showed very little or no binding to Fe(III) in normal serum. Iron(III)-binding proteins other than transferrin were shown to be present in normal serum when the native serum with [59Fe(III)] was fractionated by (NH4)2SO4 and Sephadex G-150. The presence of these proteins was observed when trace amounts of Fe(III) were added to the normal serum and when the iron-binding capacity was saturated with Fe(III) to 50% and 100%. These proteins were eluted in the void volume of Sephadex G-150 and none of them corresponded electrophoretically to transferrin. The results of the gel filtration of a mixture of [131I]-transferrin and the proteins eluted in the void volume of Sephadex G-150 were strongly in favor of the Fe(III)-proteins as being neither transferrin aggregates nor transferrin adducts with other proteins. Immunoelectrophoresis of the Sephadex G-150 void volume proteins on agar gel against the antibody to transferrin revealed the absence of transferrin. The presence of at least six proteins in this fraction was shown by immunoelectrophoresis. Positive precipitin reactions were obtained with the antibodies to α2-macroglobulin, γG-globulin, γA-globulin, and γM-globulin. At least two more proteins in this fraction remained unidentified. When the same fraction containing [59Fe(III)] was treated with the whole antisera and the precipitates were counted for radioactivity, a typical antigen-antibody reaction curve was obtained as the antibody concentration was increased. Similar experiments with this fraction and antibodies to α2-macroglobulin, γG-globulin, γA-globulin, and γM-globulin failed to show any significant radioactivity in the precipitate. Since this fraction did not contain any transferrin, it was concluded that there are proteins besides transferrin which can act as ligands for Fe(III) in normal blood plasma.

Isolation and characterization of low molecular weight Ia-like antigens from normal human serum

1981 ◽  
Vol 18 (6) ◽  
pp. 513-519 ◽  
Author(s):  
Mauro S. Sandrin ◽  
Ian F.C. McKenzie ◽  
Terry J. Higgins ◽  
Christopher R. Parish
Keyword(s):  
Molecular Weight ◽  
Human Serum ◽  
Normal Human Serum ◽  
Low Molecular Weight ◽  
Isolation And Characterization ◽  
Normal Human

The Transport of Endogenous Vitamin B12 in Normal Human Serum

1976 ◽  
Vol 51 (1) ◽  
pp. 47-52
Author(s):  
J. M. England ◽  
Margaret C. Down ◽  
Irene J. Wise ◽  
J. C. Linnell
Keyword(s):  
Vitamin B12 ◽  
Human Serum ◽  
Normal Subjects ◽  
Normal Human Serum ◽  
Normal Human ◽  
Transcobalamin I ◽  
Transcobalamin Ii

1. Serum from normal subjects has been chromatographed on Sephadex G-200 columns and the fractions containing transcobalamins 0, I and II have been identified. 2. The fractions corresponding to transcobalamin I contained, on average, 90% of the endogenous vitamin B12. Only 3% was attached to transcobalamin 0, and 7% was bound to transcobalamin II.

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