Abstract
Marked absorbance differences between monocyno- and dicyanoforms of corrinoids were observed at 358mμ as well as at 370mμ in the complete corrinoids and at 354mμ as well as at 368mμ in the incomplete corrinoid (cobinamide). Calculation of absorbance difference coefficients from the absorbance differences estimated at the respective two wave lengths described above gave approximately the same values for the complete corrinoids of the same molar concentrations. It is especially interesting that equal values were obtained for DBC and factor III (benzimidazolyl cobamides), and also for φ-B_<12> and factor A (adenyl cobamides). Satisfactory results were obtained from application of the absorbance difference coefficients to the differential determination of complete and incomplete corrinoids in the cells of propionic acid bacteria.
