Method of quantitative assay for vitamin B12 and reagent for assaying vitamin B12

摘要

The present invention is directed to a method of quantitative assay for a vitamin B₁₂-active substance which comprises a culturing marine methanol-­utilizing bacteria having B₁₂ auxotrophy in a medium for quantitative assay of the bacteria containing pyrroloquinoline-quinone and a polyoxyethylene sorbitan fatty acid ester and, quantitatively determining vitamin B₁₂ depending upon degree of growth thereof and, to a reagent for the B₁₂-active substance comprising a kit for combination of an ampoule or vial having sealed therein a dry viable bacteria composition of the marine methanol-utilizing bacteria for inoculation and an ampoule or vial having sealed therein a medium for the bacteria containing pyrroloquinoline-quinone and a polyoxyethylene sorbitan fatty acid ester, or in addition thereto, further an ampoule or vial having sealed therein a standard dilution of vitamin B₁₂ having a serial concentration.