This enzyme belongs to the family of glycosyltransferases, specifically the pentosyltransferases. The systematic name of this enzyme class is nicotinate-nucleotide:5,6-dimethylbenzimidazole phospho-D-ribosyltransferase. Other names in common use include CobT, nicotinate mononucleotide-dimethylbenzimidazole phosphoribosyltransferase, nicotinate ribonucleotide:benzimidazole (adenine) phosphoribosyltransferase, nicotinate-nucleotide:dimethylbenzimidazole phospho-D-ribosyltransferase, and nicotinate mononucleotide (NaMN):5,6-dimethylbenzimidazole phosphoribosyltransferase. This enzyme is part of the biosynthetic pathway to cobalamin (vitamin B12) in bacteria.
Vitamin B12 (cobalamin) is used as a cofactor in a number of enzyme-catalysed reactions in bacteria, archaea and eukaryotes.[4] The biosynthetic pathway to adenosylcobalamin from its five-carbon precursor, 5-aminolaevulinic acid, can be divided into three sections: (1) the biosynthesis of uroporphyrinogen III from 5-aminolaevulinic acid; (2) the conversion of uroporphyrinogen III into the ring-contracted, deacylated intermediate precorrin 6 or cobalt-precorrin 6; and (3) the transformation of this intermediate to form adenosylcobalamin.[5] Cobalamin is synthesised by bacteria and archaea via two alternative routes that differ primarily in the steps of section 2 that lead to the contraction of the macrocycle and excision of the extruded carbonmolecule (and its attached methyl group).[6] One pathway (exemplified by Pseudomonas denitrificans) incorporates molecular oxygen into the macrocycle as a prerequisite to ring contraction, and has consequently been termed the aerobic pathway. The alternative, anaerobic, route (exemplified by Salmonella typhimurium) takes advantage of a chelatedcobalt ion, in the absence of oxygen, to set the stage for ring contraction.[5]
Phosphoribosyl pyrophosphate (PRPP) is a pentose phosphate. It is a biochemical intermediate in the formation of purine nucleotides via inosine-5-monophosphate, as well as in pyrimidine nucleotide formation. Hence it is a building block for DNA and RNA. The vitamins thiamine and cobalamin, and the amino acid tryptophan also contain fragments derived from PRPP. It is formed from ribose 5-phosphate (R5P) by the enzyme ribose-phosphate diphosphokinase:
In enzymology, a precorrin-4 C11-methyltransferase is an enzyme that catalyzes the chemical reaction
In enzymology, precorrin-6A synthase (deacetylating) (EC 2.1.1.152) is an enzyme that catalyzes the chemical reaction
In enzymology, a precorrin-6A reductase (EC 1.3.1.54) is an enzyme that catalyzes the chemical reaction
In enzymology, a precorrin-3B synthase (EC 1.14.13.83) is an enzyme that catalyzes the chemical reaction
In enzymology, a cob(II)yrinic acid a,c-diamide reductase is an enzyme that catalyzes the chemical reaction
In enzymology, a precorrin-8X methylmutase is an enzyme that catalyzes the chemical reaction
The enzyme threonine-phosphate decarboxylase (EC 4.1.1.81) catalyzes the chemical reaction
In enzymology, an adenosylcobyric acid synthase (glutamine-hydrolysing) (EC 6.3.5.10) is an enzyme that catalyzes the chemical reaction
Cobalt chelatase (EC 6.6.1.2) is an enzyme that catalyzes the chemical reaction
In enzymology, a hydrogenobyrinic acid a,c-diamide synthase (glutamine-hydrolysing) (EC 6.3.5.9) is an enzyme that catalyzes the chemical reaction
The primary biochemical reaction catalyzed by the enzyme adenosylcobalamin/α-ribazole phosphatase (formerly α-ribazole phosphatase) (EC 3.1.3.73) is
In enzymology, a nicotinate phosphoribosyltransferase (EC 6.3.4.21) is an enzyme that catalyzes the chemical reaction
In enzymology, an adenosylcobinamide kinase is an enzyme that catalyzes the chemical reaction
In enzymology, an adenosylcobinamide-phosphate guanylyltransferase is an enzyme that catalyzes the chemical reaction
In molecular biology, cob(I)yrinic acid a,c-diamide adenosyltransferase EC 2.5.1.17 is an enzyme which catalyses the conversion of cobalamin into one of its coenzyme forms, adenosylcobalamin. Adenosylcobalamin is required as a cofactor for the activity of certain enzymes. AdoCbl contains an adenosyl moiety liganded to the cobalt ion of cobalamin via a covalent Co-C bond.
Cobalamin biosynthesis is the process by which bacteria and archea make cobalamin, vitamin B12. Many steps are involved in converting aminolevulinic acid via uroporphyrinogen III and adenosylcobyric acid to the final forms in which it is used by enzymes in both the producing organisms and other species, including humans who acquire it through their diet.
5,6-dimethylbenzimidazole synthase (EC 1.14.99.40, BluB) is an enzyme with systematic name FMNH2 oxidoreductase (5,6-dimethylbenzimidazole forming). This enzyme catalyses the following chemical reaction
Adenosylcobinamide-GDP ribazoletransferase is an enzyme with systematic name adenosylcobinamide-GDP:alpha-ribazole ribazoletransferase. This enzyme catalyses the following chemical reaction
Adenosylcobinamide-phosphate synthase is an enzyme with systematic name adenosylcobyric acid:(R)-1-aminopropan-2-yl phosphate ligase (ADP-forming). This enzyme catalyses the following chemical reaction
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