Application
FMN is suitable as a photopolymerization reagent in PAGE by forming free radicals in aqueous solution in the presence of light. FMN photodecomposes to leucoflavin. No free radicals are formed in the absence of oxygen, but traces of oxygen allow for leucoflavin to reoxidize with free-radical generation. The catalysts, TEMED or DMAPN, are commonly added to speed up the free radical formation. Free radicals will cause acrylamide and bis-acrylamide to polymerize to form a gel matrix which can be used for sieving macromolecules. FMN is commonly used in the stacking gel for non-denaturing PAGE because native proteins can be sensitive to persulfate ions from ammonium persulfate. Another advantage of FMN over ammonium persulfate is that it will not start polymerizing until the gel is illuminated.