3,4-dihydroxy-2-butanone-4-phosphate synthase
CLASS OF ENZYMES
EC 4.1.99.12; D-ribulose 5-phosphate formate-lyase (L-3,4-dihydroxybutan-2-one 4-phosphate-forming)
The enzyme 3,4-dihydroxy-2-butanone 4-phosphate synthase (DHBP synthase) (RibB) catalyses the conversion of D-ribulose 5-phosphate to formate and 3,4-dihydroxy-2-butanone 4-phosphate, the latter serving as the biosynthetic precursor for the xylene ring of riboflavin. In Photobacterium leiognathi, the riboflavin synthesis genes ribB (DHBP synthase), ribE (riboflavin synthase), ribH (lumazine synthase) and ribA (GTP cyclohydrolase II) all reside in the lux operon.