An assay for intrinsic factor based on blocking of the R binder of gastric juice by cobinamide.

An in vitro assay for measurement of gastric juice intrinsic factor (IF) was developed based on the ability of the cobinamide (Cbi) [(CN, OH) Cbi] to bind to the gastric juice R-type binders of cobalamin (Cbl) and not to the IF binder. Subsequently added radioactive Cbl, CN-[57Co] Cbl, binds only to the IF binders and allows for direct measurement of this Cbl binding protein. This Cbi blocking assay was found to function as well as the more conventional methods of IF measurement, G-100 column chromatography, and IF blocking antibody assay. The present assay has the advantage of eliminating the need for elaborate forms of protein separation and does not rely on a source of antibody.

[1]  D. Mollin,et al.  A radioisotope dilution assay for unlabelled vitamin B12-intrinsic factor complex employing the binding intrinsic factor antibody: probable evidence for two types of binding antibody. , 2009, Scandinavian journal of haematology.

[2]  J. F. Kolhouse,et al.  Absorption, plasma transport, and cellular retention of cobalamin analogues in the rabbit. Evidence for the existence of multiple mechanisms that prevent the absorption and tissue dissemination of naturally occurring cobalamin analogues. , 1977, The Journal of clinical investigation.

[3]  C. Hall.  The carriers of native vitamin B12 in normal human serum. , 1977, Clinical science and molecular medicine.

[4]  J. Begley,et al.  Congenital deficiency of human R-type binding proteins of cobalamin. , 1977, American journal of human genetics.

[5]  E. Jacob,et al.  A simple assay of intrinsic factor-vitamin B12 complex employing the binding intrinsic factor antibody , 1972, Journal of clinical pathology.

[6]  M. D. Turner,et al.  Gel filtration of vitamin B 12-binding materials from human gastric juice and gastric mucosa. , 1966, Biochimica et biophysica acta.

[7]  Rothenberg Sp.  A radioimmunoassay for human intrinsic factor. , 1966 .

[8]  L. Wasserman,et al.  RAPID CHARCOAL ASSAY FOR INTRINSIC FACTOR (IF), GASTRIC JUICE UNSATURATED B12 BINDING CAPACITY, ANTIBODY TO IF, AND SERUM UNSATURATED B12 BINDING CAPACITY. , 1965, Blood.

[9]  G. Glass,et al.  PAPER ELECTROPHORETIC ANALYSIS OF B12 BINDING IN HUMAN GASTRIC JUICE. , 1964, Clinica chimica acta; international journal of clinical chemistry.

[10]  M. Sleisenger,et al.  Fractionation of the nondialyzable components of normal human gastric juice by starch gel electrophoresis. , 1961, Gastroenterology.

[11]  J. Cannon,et al.  787. Chemistry of the vitamin B12 group. Part III. The course of hydrolytic degradations , 1953 .