抄録
1. An unidentified orange-yellow colored compound was obtained from the cells of Pr. shermanii harvested from the medium containing cobinamide exogenously added. The compound exhibited the coenzyme activity in the propylene glycol-propionaldehyde conversion system of Abeles and Lee. Its Km value was 6×10-6M, 20 times as great as that of 5, 6-dimethylbenz imidazolyl cobamide coenzyme (DBCC).
2. The compound moved to the cathode 1.5 times faster than cobinamide cyanide, hydroxo- and cyanocobalamins, and DBCC at acidic pH levels in paper ionophoresis. After treatment with cyanide solution, the product showed the same mobility as cobinamide cyanide.
3. The shape of its absorption spectrum in a neutral solution was analogous to that of DBCC except the difference in the wave length of the absorption maximum at 450mμ.
The spectrum was replaced by a spectrum with double peaks at 350 and 500 to 550mμ by the exposure to light and changed to the same spectrum as that of cobinamide dicyanide after cyanide treatment.
4. The compound was converted to the violet dicyano form at acidic pH levels as well as under alkaline condition. This conversion is known to be specific for cobinamide analogues.
5. The microbiological activity of the compound was poor against E. coli No. 215 which is known to show a weak response to cobinamide and its derivatives.
6. From these results it would be concluded that the orange-yellow compound is the coenzyme form of cobinamide which has the structure as shown in Fig. 8. The authors tentatively designated it “cobinamide coenzyme”.
