Isolation and structure of a new factor of the vitamin B12 group: guanosine diphosphate factor B

Abstract

The nature of the violet pigment formed during the reaction is not known. Attempts to isolate the pigment by chromatography and solvent extrac- tion were unsuccessful. It was observed, however, that on addition of mineral acid the violet reaction mixture became orange and this process was reversible. This colour change occurred at pH 9-5- 10.1, which may be taken to indicate that the violet product is anionic in nature, possibly in- volving a keto-enol system.