title: Biosynthesis of riboflavin. Enzymatic formation of 6,7-dimethyl-8-ribityllumazine by heavy riboflavin synthase from Bacillus subtilis.
abstract: The beta subunits of heavy riboflavin synthase catalyze the formation of 6,7-dimethyl-8-ribityllumazine from 5-amino-6-ribitylamino-2,4(1H,3H)-pyrimidinedione and a carbohydrate phosphate, Compound X. 5-Amino-6-ribitylamino-2,4(1H,3H)-pyrimidinedione 5'-phosphate is not a substrate for the enzyme, although it is an established intermediate in the biosynthesis of riboflavin. It follows that this pyrimidine phosphate must be dephosphorylated prior to the formation of 6,7-dimethyl-8-ribityllumazine.
mesh_terms: D001412:Bacillus subtilis / Q000201:enzymology*; D005415:Flavins / Q000378:metabolism; D046911:Macromolecular Substances; D008956:Models, Chemical; D011621:Pteridines / Q000378:metabolism*; D012256:Riboflavin / Q000096:biosynthesis*; D012258:Riboflavin Synthase / Q000378:metabolism*; D012274:Ribulosephosphates / Q000378:metabolism; D014166:Transferases / Q000378:metabolism*
chemical_list: D005415:Flavins; D046911:Macromolecular Substances; D011621:Pteridines; D012274:Ribulosephosphates; C001559:7,8-dimethylalloxazine; C001061:6,7-dimethyl-8-ribityllumazine; D014166:Transferases; D012258:Riboflavin Synthase; D012256:Riboflavin