1.13.11.79: aerobic 5,6-dimethylbenzimidazole synthase
This is an abbreviated version!
For detailed information about aerobic 5,6-dimethylbenzimidazole synthase, go to the full flat file.
Reaction
Synonyms
BluB, bluB/cobT2, DMB-synthase, EC 1.14.99.40, flavin destructase, flavin destructase enzyme
ECTree
1.13.11.79 aerobic 5,6-dimethylbenzimidazole synthaseAdvanced search results
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Substrates Products
Substrates Products on EC 1.13.11.79 - aerobic 5,6-dimethylbenzimidazole synthase
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SUBSTRATE 
PRODUCT
REACTION DIAGRAM
ORGANISM
UNIPROT
COMMENTARY
(Substrate)
(Substrate)
LITERATURE
(Substrate)
(Substrate)
COMMENTARY
(Product)
(Product)
LITERATURE
(Product)
(Product)
Reversibility
r=reversible
ir=irreversible
?=not specified
r=reversible
ir=irreversible
?=not specified
FMNH2 + NADH + H+ + O2 + alloxan
5,6-dimethylbenzimidazole + D-erythrose 4-phosphate + NAD+ + dialuric acid
FMNH2 + NADH + H+ + O2 + H2O
5,6-dimethylbenzimidazole + D-erythrose 4-phosphate + NAD+ + ?
-
-
-
?
FMNH2 + NADPH + H+ + O2
5,6-dimethylbenzimidazole + D-erythrose 4-phosphate + NADP+ + ?
-
-
-
-
r
FMNH2 + O2
5,6-dimethylbenzimidazole + D-erythrose 4-phosphate + dialiric acid + pyrimidinetrione + alloxan
-
the rate of formation of the intermediate product unprotonated C4a-peroxyflavin is influenced by substitutions at C8 of FMN
-
-
?
FMNH2 + NADH + H+ + O2
5,6-dimethylbenzimidazole + D-erythrose 4-phosphate + NAD+ + ?
-
-
-
-
?
FMNH2 + NADH + H+ + O2
5,6-dimethylbenzimidazole + D-erythrose 4-phosphate + NAD+ + ?
-
5,6-dimethylbenzimidazole is the lower axial ligand of vitamin B12, i.e. cobalamin
-
?
FMNH2 + NADH + H+ + O2
5,6-dimethylbenzimidazole + D-erythrose 4-phosphate + NAD+ + ?
BluB fragments a flavin isoalloxazine ring
-
-
?
FMNH2 + NADH + H+ + O2 + alloxan
5,6-dimethylbenzimidazole + D-erythrose 4-phosphate + NAD+ + dialuric acid
-
-
-
-
?
FMNH2 + NADH + H+ + O2 + alloxan
5,6-dimethylbenzimidazole + D-erythrose 4-phosphate + NAD+ + dialuric acid
-
in the first stage, BluB catalyzes the incorporation of dioxygen, and the fragmentation of the isoalloxazine ring of FMNH2 to form alloxan and the ribityl dimethylphenylenediimine. In the second stage, BluB exploits alloxan as a multifunctional cofactor, such as a proton donor, a proton acceptor, and a hydride acceptor, to catalyze the remaining no fewer than 10 steps of the reaction. The retro-aldol cleavage of the C1'-C2' bond of intermediate ribityl dimethylphenylenediimine is the rate-determining step, active site model of BluB, overview. The highly conserved residue Asp32 plays critical roles in multiple steps of the conversion by serving as a proton acceptor or a proton shuttle, and another conserved residue Ser167 plays its catalytic role mainly in the rate-determining step by stabilizing the protonated retro-aldol precursor. Formation of peroxyflavin intermediate, overview
-
-
?
FMNH2 + O2
5,6-dimethylbenzimidazole + ?
-
FMNH2 reacts with oxygen to yield flavin hydroperoxide, which then undergoes a ring expansion with loss of a water molecule to produce intermediate A. This disintegrates further as a result of four hydrolysis reactions in which it is attacked by water molecules. The resulting diaminobenzene product undergoes two oxidation reactions, to form 5,6-dimethylbenzimidazole
-
-
?
FMNH2 + O2
5,6-dimethylbenzimidazole + D-erythrose 4-phosphate + other product(s)
-
-
-
?
FMNH2 + O2
5,6-dimethylbenzimidazole + D-erythrose 4-phosphate + other product(s)
-
-
-
?
FMNH2 + O2
5,6-dimethylbenzimidazole + D-erythrose 4-phosphate + urea + ?
-
-
-
-
?
FMNH2 + O2
5,6-dimethylbenzimidazole + D-erythrose 4-phosphate + urea + ?
-
-
-
-
?
