| '''Lumazine synthase''' ({{EC number|2.5.1.78}}, ''6,7-dimethyl-8-ribityllumazine synthase'', ''6,7-dimethyl-8-ribityllumazine synthase 2'', ''6,7-dimethyl-8-ribityllumazine synthase 1'', ''lumazine synthase 2'', ''lumazine synthase 1'', ''type I lumazine synthase'', ''type II lumazine synthase'', ''RIB4'', ''MJ0303'', ''RibH'', ''Pbls'', ''MbtLS'', ''RibH1 protein'', ''RibH2 protein'', ''RibH1'', ''RibH2'') is an [[enzyme]] with system name ''5-amino-6-(D-ribitylamino)uracil butanedionetransferase''.<ref>{{cite journal | title = Biosynthesis of riboflavin. Studies on the reaction mechanism of 6,7-dimethyl-8-ribityllumazine synthase |author = Kis, K., Volk, R. and Bacher, A. |journal = Biochemistry |year = 1995 |volume = 34 |pages = 2883–2892 |pmid = 7893702 | doi = 10.1021/bi00009a019 | issue = 9}}</ref><ref>{{cite journal | title = The ''Saccharomyces cerevisiae'' RIB4 gene codes for 6,7-dimethyl-8-ribityllumazine synthase involved in riboflavin biosynthesis. Molecular characterization of the gene and purification of the encoded protein |author = Garcia-Ramirez, J.J., Santos, M.A. and Revuelta, J.L. |journal = J. Biol. Chem. |year = 1995 |volume = 270 |pages = 23801–23807 |pmid = 7559556 | doi = 10.1074/jbc.270.40.23801 | issue = 40}}</ref><ref>{{cite journal | title = Biosynthesis of riboflavin: structure and mechanism of lumazine synthase |author = Bacher, A., Fischer, M., Kis, K., Kugelbrey, K., Mörtl, S., Scheuring, J., Weinkauf, S., Eberhardt, S., Schmidt-Bäse, K., Huber, R., Ritsert, K., Cushman, M., Ladenstein, R. |journal = Biochem. Soc. Trans. |year = 1996 |volume = 24 |pages = 89–94 |pmid = 8674771 | issue = 1}}</ref><ref>{{cite journal | title = Biosynthesis of riboflavin. Lumazine synthase of ''Escherichia coli'' |author = Mörtl, S., Fischer, M., Richter, G., Tack, J., Weinkauf, S. and Bacher, A. |journal = J. Biol. Chem. |year = 1996 |volume = 271 |pages = 33201–33207 |pmid = 8969176 | doi = 10.1074/jbc.271.52.33201 | issue = 52}}</ref><ref>{{cite journal | title = Biosynthesis of riboflavin: lumazine synthase and riboflavin synthase |author = Bacher, A., Eberhardt, S., Fischer, M., Mortl, S., Kis, K., Kugelbrey, K., Scheuring, J. and Schott, K. |journal = Methods Enzymol. |year = 1997 |volume = 280 |pages = 389–399 |pmid = 9211334 | doi = 10.1016/S0076-6879(97)80130-9 | series = Methods in Enzymology | isbn = 9780121821814}}</ref><ref>{{cite journal | title = The 18-kDa cytoplasmic protein of Brucella species - an antigen useful for diagnosis - is a lumazine synthase |author = Goldbaum, F.A., Velikovsky, C.A., Baldi, P.C., Mortl, S., Bacher, A. and Fossati, C.A. |journal = J. Med. Microbiol. |year = 1999 |volume = 48 |pages = 833–839 |pmid = 10482294 | doi = 10.1099/00222615-48-9-833 | issue = 9}}</ref><ref>{{cite journal | title = Plant riboflavin biosynthesis. Cloning, chloroplast localization, expression, purification, and partial characterization of spinach lumazine synthase |author = Jordan, D.B., Bacot, K.O., Carlson, T.J., Kessel, M. and Viitanen, P.V. |journal = J. Biol. Chem. |year = 1999 |volume = 274 |pages = 22114–22121 |pmid = 10419541 | doi = 10.1074/jbc.274.31.22114 | issue = 31}}</ref><ref>{{cite journal | title = X-ray structure analysis and crystallographic refinement of lumazine synthase from the hyperthermophile ''Aquifex aeolicus'' at 1.6 Å resolution: determinants of thermostability revealed from structural comparisons |author = Zhang, X., Meining, W., Fischer, M., Bacher, A. and Ladenstein, R. |journal = J. Mol. Biol. |year = 2001 |volume = 306 |pages = 1099–1114 |pmid = 11237620 | doi = 10.1006/jmbi.2000.4435 | issue = 5}}</ref><ref>{{cite journal | title = Biosynthesis of riboflavin: 6,7-dimethyl-8-ribityllumazine synthase of ''Schizosaccharomyces pombe'' |author = Fischer, M., Haase, I., Feicht, R., Richter, G., Gerhardt, S., Changeux, J.P., Huber, R. and Bacher, A. |journal = Eur. J. Biochem. |year = 2002 |volume = 269 |pages = 519–526 |pmid = 11856310 | doi = 10.1046/j.0014-2956.2001.02674.x | issue = 2}}</ref><ref>{{cite journal | title = Design, synthesis, and evaluation of 6-carboxyalkyl and 6-phosphonoxyalkyl derivatives of 7-oxo-8-ribitylaminolumazines as inhibitors of riboflavin synthase and lumazine synthase |author = Cushman, M., Yang, D., Gerhardt, S., Huber, R., Fischer, M., Kis, K. and Bacher, A. |journal = J. Org. Chem. |year = 2002 |volume = 67 |pages = 5807–5816 |pmid = 12153285 | doi = 10.1021/jo0201631 | issue = 16}}</ref><ref>{{cite journal | title = Biosynthesis of riboflavin in archaea. 6,7-dimethyl-8-ribityllumazine synthase of ''Methanococcus jannaschii'' |author = Haase, I., Mortl, S., Kohler, P., Bacher, A. and Fischer, M. |journal = Eur. J. Biochem. |year = 2003 |volume = 270 |pages = 1025–1032 |pmid = 12603336 | doi = 10.1046/j.1432-1033.2003.03478.x | issue = 5}}</ref><ref>{{cite journal | title = Crystal structure of lumazine synthase from ''Mycobacterium tuberculosis'' as a target for rational drug design: binding mode of a new class of purinetrione inhibitors |author = Morgunova, E., Meining, W., Illarionov, B., Haase, I., Jin, G., Bacher, A., Cushman, M., Fischer, M. and Ladenstein, R. |journal = Biochemistry |year = 2005 |volume = 44 |pages = 2746–2758 |pmid = 15723519 | doi = 10.1021/bi047848a | issue = 8}}</ref><ref>{{cite journal | title = Lumazine synthase from ''Candida albicans'' as an anti-fungal target enzyme: structural and biochemical basis for drug design |author = Morgunova, E., Saller, S., Haase, I., Cushman, M., Bacher, A., Fischer, M. and Ladenstein, R. |journal = J. Biol. Chem. |year = 2007 |volume = 282 |pages = 17231–17241 |pmid = 17446177 | doi = 10.1074/jbc.M701724200 | issue = 23}}</ref><ref>{{cite journal |author=Fornasari MS, Laplagne DA, Frankel N, Cauerhff AA, Goldbaum FA, Echave J |title=Sequence determinants of quaternary structure in lumazine synthase |journal=Mol. Biol. Evol. |volume=21 |issue=1 |pages=97–107 |year=2004 |pmid=14523158 |doi=10.1093/molbev/msg244|url=http://mbe.oxfordjournals.org/cgi/content/abstract/21/1/97}}</ref> This enzyme [[catalysis|catalyses]] the following [[chemical reaction]]
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