Abstract
One of the unknown riboflavin compounds which had previously been found by us in the cultural solution of the synthetic medium with the mutant of Aspergillus oryzae, was proved to be identical with riboflavinylglucoside isolated by Whitby with rat liver. In the present experiment, it was found that this mold easily synthesized not only riboflavinylglucoside, but also several sugar compounds of riboflavin in the reaction mixture containing riboflavin and maltose. Factors of the synthesis of riboflavinylglucoside were investigated, and soluble starch, salicin, lactose, melibiose, sucrose and glucose were found to be able to replace maltose as glucose donor, while riboflavin monophosphate could not replace riboflavin when phosphatase-free enzyme was used. It was suggested that the biochemical significance of these sugar compounds would be related to polysaccharide synthesis by Aspergillus oryzae.
