A solid-phase enzyme-linked assay for vitamin B12

Catherine D. Tsalta, Sara A. Rosario, Geun Sig Cha, Leonidas G. Bachas, Mark E. Meyerhoff

Research output: Contribution to journalArticle

7 Scopus citations


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 3×10-10-1×10-8M (using 100 μl sample) with high selectivity over other biological molecules.

Original languageEnglish (US)
Pages (from-to)65-73
Number of pages9
JournalMikrochimica Acta
Issue number1-2
StatePublished - Jan 1989


  • competitive binding assays
  • enzyme-vitamin conjugates
  • vitamin B (cyanocobalamin)
  • vitamin tablet analyses

ASJC Scopus subject areas

  • Analytical Chemistry

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    Tsalta, C. D., Rosario, S. A., Cha, G. S., Bachas, L. G., & Meyerhoff, M. E. (1989). A solid-phase enzyme-linked assay for vitamin B12. Mikrochimica Acta, 97(1-2), 65-73. https://doi.org/10.1007/BF01197285