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A Comparison of the Properties of Chicken Serum with Other Vitamin B 12 Binding Proteins Used in Radioisotope Dilution Methods for Measuring Serum Vitamin B 12 Concentrations
Author(s) -
Newmark P. A.,
Green R.,
Musso A. M.,
Mollin D. L.
Publication year - 1973
Publication title -
british journal of haematology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.907
H-Index - 186
eISSN - 1365-2141
pISSN - 0007-1048
DOI - 10.1111/j.1365-2141.1973.tb01747.x
Subject(s) - ionic strength , chemistry , dilution , vitamin , chromatography , vitamin b , serum concentration , biochemistry , endocrinology , biology , aqueous solution , organic chemistry , thermodynamics , physics
S ummary . The effects of pH, ionic strength, and vitamin B 12 concentration on the vitamin B 12 ‐binding capacities of chicken serum, normal human serum, chronic myelogenous leukaemia serum, and hog intrinsic factor concentrates are compared. The influence of pH on B 12 ‐binding capacity was shown to be greatest at low pH and that of ionic strength was most evident below 0.1 ionic strength, particularly at acidic pH. The effect of B 12 concentration on B 12 ‐binding capacity was shown to vary with different binders, the pH of binding, and the time of incubation. It was possible to select conditions for carrying out the binding of B 12 to chicken serum so that the amount of B 12 bound was virtually unaffected by the kind of variations in pH, ionic strength, or concentration of B 12 that could occur in a radioisotope dilution assay of serum vitamin B 12 . Under these conditions it was further demonstrated that the binding was unaffected by the presence of denatured human serum. In addition chicken serum had a very great binding capacity and affinity for B 12 , was very stable on storage and was compatible with the use of protein‐coated charcoal. Some conclusions on the optimal use of B 12 ‐binding protein in the radioisotope dilution assay of serum vitamin B 12 are made and the high potentiality of chicken serum in such a system is suggested.