How does riboflavin initiates gel polymerization?

(Last Updated On: July 21, 2021)
A structure of riboflavin
A structure of riboflavin. Image: Yikrazuul via Common Wikimedia

Flavin is a common name for heterotricyclic organic compounds that are based on pteridine. A ribose molecule attached to the flavin nucleus through an amine bond to the N10 atom is called as riboflavin. Riboflavin is a key component of different cofactors together with it plays central roles in metabolism.

Riboflavin containing cofactors are flavin mononucleotide or flavin-5-monophosphate, flavin adenine dinucleotide (FAD). They play essential roles in the oxidation reaction being part of the enzymes (flavoproteins) such as NADH/NADPH dehydrogenase.

However, riboflavin can also be used in the biochemical experiments to carry out protein separation by acrylamide gel electrophoresis during which it acts as an initiator of the polymerization of the acrylamide and bisacrylamide. Instead of using ammonium persulfate and TEMED, riboflavin can be used.

However, it needs light to be activated and can only be used with the non-denaturing condition, because some proteins are sensitive to denaturation by persulfate free radicals generated from ammonium persulfate. Light causes activation of the riboflavin to generate free radicals that react with the acrylamide and bisacrylamide to be polymerized and cross-linked.

Riboflavin induced polymerization has some advances over the APS and TEMED based polymerization, such as polymerization will not start until the gel is illuminated with the light.

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