3,4-dihydroxy-2-butanone-4-phosphate synthase

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PDB 1g58 EBI.jpg
crystal structure of 3,4-dihydroxy-2-butanone 4-phosphate synthase gold derivative
Symbol DHBP_synthase
Pfam PF00926
InterPro IPR000422
SCOP 1iez

In molecular biology, 3,4-dihydroxy-2-butanone 4-phosphate synthase (DHBP synthase) (RibB) EC is an enzyme which 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.[1] 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.[2] RibB is sometimes found as a bifunctional enzyme with GTP cyclohydrolase II that catalyses the first committed step in the biosynthesis of riboflavin. No sequences with significant homology to DHBP synthase are found in the metazoa.


  1. ^ Richter G; Krieger C; Volk R; Kis K; Ritz H; Gotze E; Bacher A (1997). "Biosynthesis of riboflavin: 3,4-dihydroxy-2-butanone-4-phosphate synthase". Meth. Enzymol. 280: 374–82. PMID 9211332. doi:10.1016/S0076-6879(97)80128-0. 
  2. ^ Lin JW; Chao YF; Weng SF (June 2001). "Riboflavin synthesis genes ribE, ribB, ribH, ribA reside in the lux operon of Photobacterium leiognathi". Biochem. Biophys. Res. Commun. 284 (3): 587–95. PMID 11396941. doi:10.1006/bbrc.2001.5013. 

This article incorporates text from the public domain Pfam and InterPro IPR000422