PHOTOCHEMICAL REACTIONS OF FORMYLMETHYLFLAVIN AND RIBOFLAVIN

Abstract

Formylmethylflavin (FMF) is a major intermediate product in the aerobic and anaerobic photolysis of riboflavin (RF) and is highly sensitive to light and hydrolysis. It is more sensitive to light as compared to RF. FMF is further degraded into lumichrome (LC), carboxymethylflavin (CMF) in acidic medium, and LC, CMF and lumiflavin (LF) in alkaline medium. When FMF is exposed to light it is degraded in to LC and LF via a photoreduction and CMF through photooxidation pathways. In aerobic and anaerobic conditions, RF when exposed to light is excited to singlet state (1RF) and from singlet to triplet state (3RF). This is followed by the conversion of 3RF into a semiquinone radical (RFH) and this radical further disproportionate to form an oxidized RF and a cyclic intermediate, which is further oxidized to FMF and degradation products (LC, LF, CMF).

Keywords

• Formylmethylflavin
• riboflavin
• aerobic and anaerobicphotolysis.