抄録
This paper deals with the properties of vitamin B_<12>-active substances produced by the incubation of washed cells of Lactobacillus leichmannii with an excess amount of hydroxocobalamin for 24 hours at 37℃. The vitamin B_<12>-active substance in the bacterial cells, though the amount was only 0.5% of the total vitamin B_<12> in the incubation mixture, showed the similar behaviors to those of DBCC in spectrophotometry, paper and ion exchange chromatographies and paper electrophoresis. The vitamin B_<12>-active substances in the supernatant were separated by DEAE-cellulose chromatography to a pass-through fraction D-1 and a retained fraction D-2. The former behaved analogously to DBCC in paper electrophoresis performed at the pH levels, 2.5,3.5 and 7.0,respectively. Its absorption spectrum and the changes caused by either illumination or cyanide treatment were similar to those of DBCC. The latter, eluted from DEAE-cellulose with 0.1M acetate buffer (pH 4.7), showed the analogous spectroscopic behaviors to DBCC as well as D-1,but less cationic characters in paper electrophoresis at several pH levels. Both D-1 and D-2 exhibited the coenzyme activities in Abeles・Lee's diol dehydrase system, though somewhat smaller than that of DBCC. It remains unsolved whether the activities of these fractions were substantially small or lowered by the contaminated impurities, e. g. hydroxocobalamin.
