Article

A solid-phase enzyme-linked assay for vitamin B12

Kallestad Lab., Inc. 200 Lake Hazeline 55318 Chaska MN USA; Department of Chemistry University of Kentucky 40506 Lexington KY USA
Microchimica Acta (Impact Factor: 3.43). 12/1988; 97(1):65-73. DOI: 10.1007/BF01197285
Source: OAI

ABSTRACT A new solid-phase enzyme-linked competitive binding assay for vitamin B12 (cyanocobalamin) is described. The assay is based on the competition between analyte B12 molecules and a glucose-6-phosphate dehydrogenase-vitamin B12 conjugate for a limited number of R-protein binding sites immobilized on sepharose particles. After appropriate incubation and washing steps, the enzyme activity bound to the solid-phase is inversely related to the concentration of B12 in the sample. Under optimized conditions, the method can detect B12 in the range of 310–10–110–8
M (using 100l sample) with high selectivity over other biological molecules.

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