Requires Mn2+?or Co2+. While FAD was the best substrate tested [2], the enzyme also splits ribonucleoside diphosphate-X compounds in which X is an acyclic or cyclic monosaccharide or derivative bearing an X-OH group that is able to attack internally the proximal phosphorus with the geometry necessary to form a P=X product; either a five-atom monocyclic phosphodiester or a?cis-bicyclic phosphodiester-pyranose fusion. The reaction is strongly inhibited by ADP or ATP but is unaffected by the presence of the product, cFMN.
