Methylglyoxal synthetase

While the mechanism for the formation of (35) has not been determined, an internal oxidation-reduction of the ribityl group (similar to that catalyzed by methylglyoxal synthetase) to afford the free diketone (38) which reacts with a second molecule of (32), appears plausible. In support of this it has been shown (82JA3754) that label from [1-3C]ribose is incorporated at the C-5 of riboflavin (corresponding to the 6-methyl of 33) and not at C-8. 

S)-[l-2H,3H]ethylene glycol, respectively, to racemic acetaldehyde. Racemic acetaldehyde is also formed in the cleavage of 2-deoxyribose 5-phosphate by a specific aldolase (90), and the incubation of stereospecifically labeled dihy-droxyacetone phosphate with methylglyoxal synthetase gives racemic methyl-glyoxal (pyruvic aldehyde) (91). 

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