BIOSYNTHESIS OF VITAMIN B₁₂ FROM CO⁶⁰-LABELED COBALT-PORPHYRIN BY AGED CELL HOMOGENATE OF FUGLENA GRACILIS

Abstract

1. Biosynthesis of vitamin B₁₂ by aged cell homogenate of B₁₂-nonproducing microbe was tested, and it was found by bioautography that the in vitro formation of vitamin B₁₂ from cobalt-porphyrin and 5, 6-dimethylbenzimidazole was always positive.
2. Further evidence was obtained by using Co⁶⁰-labeled Co-porphyrin, and biosynthesis of Co⁶⁰-labeled vitamin B₁₂ was confirmed by radioautography.
3. From these findings it is concluded that cobalt-porphyrin may be available for the formation of vitamin B₁₂ in vitro by the intracellular enzyme of an Euglena strain which is ordinarily an nonproducer of vitamin B₁₂.