Riboflavin synthase (alpha subunit); Catalyzes the dismutation of two molecules of 6,7-dimethyl-8- ribityllumazine, resulting in the formation of riboflavin and 5-amino- 6-(D-ribitylamino)uracil.

Fused diaminohydroxyphosphoribosylaminopyrimidine deaminase; Converts 2,5-diamino-6-(ribosylamino)-4(3h)-pyrimidinone 5'- phosphate into 5-amino-6-(ribosylamino)-2,4(1h,3h)-pyrimidinedione 5'- phosphate; In the C-terminal section; belongs to the HTP reductase family.

RNA-binding cryptic riboflavin kinase regulatory protein; May be directly involved in the regulation of the rib genes. C-terminal part of RibR specifically binds to RFN of the rib leader of the riboflavin biosynthetic operon. The RFN element is a sequence within the rib-leader mRNA reported to serve as a receptor for an FMN- dependent riboswitch. Possibly, RibR produces the comodulator FMN through its own N-terminal flavokinase activity. FMN-activated RibR may stabilize the anti-anti terminator structure of RFN mRNA, causing transcription termination of the rib genes in trans.

Fused GTP cyclohydrolase II and 3,4-dihydroxy-2-butanone 4-phosphate synthase; Catalyzes the conversion of D-ribulose 5-phosphate to formate and 3,4-dihydroxy-2-butanone 4-phosphate; In the N-terminal section; belongs to the DHBP synthase family.

6,7-dimethyl-8-ribityllumazine synthase, beta subunit; Catalyzes the formation of 6,7-dimethyl-8-ribityllumazine by condensation of 5-amino-6-(D-ribitylamino)uracil with 3,4-dihydroxy-2- butanone 4-phosphate. This is the penultimate step in the biosynthesis of riboflavin. Is able to use the non-natural R enantiomer of 3,4- dihydroxy-2-butanone 4-phosphate as a substrate, but with less efficiency than the natural S enantiomer. Cannot use unphosphorylated 3,4-dihydroxy-2-butanone, 3,4-dihydroxy-2-butanone 3-phosphate or diacetyl as substrates.

FMN-containing NADPH-linked nitro/flavin reductase; Reduces FMNH(2) to FMN, with NADPH as reductant. It also reduces nitroaromatic compounds, quinones and azo dyes.

NADPH-FMN oxidoreductase (nitroreductase); Reduces FMNH(2) to FMN, with NADH or NADPH as reductant. It also reduces nitroaromatic compounds, quinones, chromates and azo dyes. It could supply the reduced form of FMN to luciferase-like protein and contribute to the degradation of aromatic compounds. Belongs to the flavin oxidoreductase frp family.

Cytidylate kinase; Evidence 1a: Function experimentally demonstrated in the studied strain; enzyme.

FMN permease; Mediates uptake of riboflavin and roseoflavin, a toxic riboflavin analog; may also transport FMN. Probably a riboflavin- binding protein that interacts with the energy-coupling factor (ECF) ABC-transporter complex. Unlike classic ABC transporters this ECF transporter provides the energy necessary to transport a number of different substrates. The substrates themselves are bound by transmembrane, not extracytoplasmic soluble proteins (By similarity). Belongs to the prokaryotic riboflavin transporter (P-RFT) (TC 2.A.87) family.