Reaction: L-glutamate + FMN + O2 + H2O + 3 acceptor = 2-oxoglutarate + 8-amino-8-demethylriboflavin 5′-phosphate + CO2 + 3 reduced acceptor (overall reaction)
(1a) FMN + O2 = 8-demethyl-8-formylriboflavin 5′-phosphate + H2O
(1b) 8-demethyl-8-formylriboflavin 5′-phosphate + H2O + acceptor = 8-carboxy-8-demethylriboflavin 5′-phosphate + reduced acceptor
(1c) L-glutamate + 8-carboxy-8-demethylriboflavin 5′-phosphate + H2O + 2 acceptor = 2-oxoglutarate + 8-amino-8-demethylriboflavin 5′-phosphate + CO2 + 2 reduced acceptor
For diagram of reaction click here.
Glossary: roseoflavin = 8-demethyl-8-(dimethylamino)riboflavin
Other name(s): rosB (gene name)
Systematic name: L-glutamate:FMN aminotransferase (oxidizing, decarboxylating)
Comments: The enzyme, characterized from the bacterium Streptomyces davawensis, has the activities of an oxidoreductase, a decarboxylase, and an aminotransferase. Its combined actions result in the replacement of a methyl substituent of one of the aromatic rings of FMN by an amino group, a step in the biosynthetic pathway of roseoflavin. The reaction requires thiamine for completion.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, CAS registry number:
1. Schwarz, J., Konjik, V., Jankowitsch, F., Sandhoff, R. and Mack, M. Identification of the key enzyme of roseoflavin biosynthesis. Angew Chem Int Ed Engl 55 (2016) 6103-6106. [PMID: 27062037]
2. Jhulki, I., Chanani, P.K., Abdelwahed, S.H. and Begley, T.P. A remarkable oxidative cascade that replaces the riboflavin C8 methyl with an amino group during roseoflavin biosynthesis. J. Am. Chem. Soc. 138 (2016) 8324-8327. [PMID: 27331868]
3. Konjik, V., Brunle, S., Demmer, U., Vanselow, A., Sandhoff, R., Ermler, U. and Mack, M. The crystal structure of RosB: insights into the reaction mechanism of the first member of a family of flavodoxin-like enzymes. Angew Chem Int Ed Engl 56 (2017) 1146-1151. [PMID: 27981706]