188.8.131.52 - Nicotinate-nucleotide diphosphorylase (carboxylating)
- Nicotinate-nucleotide pyrophosphorylase (carboxylating).
- Quinolinate phosphoribosyltransferase (decarboxylating).
CO2 + diphosphate + nicotinate beta-D-ribonucleotide = 5-phospho-alpha-D-ribose 1-diphosphate + 2 H(+) + quinolinate
There are no Cofactors for this Enzyme
Quinolinic acid phosphoribosyltransferase from Mycobacterium Tuberculosis (Mt-QAPRTase) is required for the de novo biosynthesis of NAD in both prokaryotes and eukaryotes (equivalent enzyme). The enzyme catalyses the reaction between quinolinic acid (QA) and 5-phosphoribosyl-1-pyrophosphate (PRPP), to yield nicotinic acid mononucleotide (NAMN), pyrophosphate and CO2, the latter resulting from decarboxylation at position 2 of the quinolinate ring.
QAPRTase has been grouped with other phosphoribosyltransferases, (PRTases) that catalyse chemically similar phosphoribosyl transfer reactions using the substrate PRPP. The PRTases are involved in de novo and salvage reactions of nucleotide synthesis, as well as in histidine and tryptophan biosynthesis [PMID:9016724]. To date, crystal structures have been determined for several PRTase enzymes and all show a common 'PRTase fold' (the 'type I' fold) composed of a central beta sheet, of five beta strands, surrounded by alpha helices. The fold contains a common recognition motif of thirteen residues which is critical for PRPP binding and catalysis. However, as type II enzymes like Mt-QAPRTase lack the type I PRPP-binding motif and have TIM barrel-like structure, it becomes possible that there might be at least two different types of PRTase fold [PMID:9016724]. Despite their structural differences, it has been suggested TI and TII indeed still have the same catalytic mechanism but more work is needed to understand this fully.
|AA||Uniprot||Uniprot Resid||PDB||PDB Resid|
inferred reaction step, dephosphorylation, intermediate formation, heterolysis, intermediate terminated, bimolecular nucleophilic addition, rate-determining step, proton transfer, bond polarisation, overall reactant used, unimolecular elimination by the conjugate base, intermediate collapse, native state of enzyme is not regenerated, decarboxylation, overall product formed
Organism KM Value [mM] Substrate Comment Salmonella enterica subsp. enterica serovar Typhimurium 0.00004 5-phospho-alpha-D-ribose 1-diphosphate mutant E214A
There are no reaction parameters information for this Enzyme.
Organism pH Range Comment Sus scrofa 5.2 - 7.8 half maximal activity at pH 5.2 and pH 7.8 Mycobacterium tuberculosis 5.2 - 11 activity cannot be detected at pH values below 5.2 and above 11.0 Bos taurus 6.4 - 7.3 pH 6.4: about 50% of maximal activity, pH 7.3: about 55% of maximal activity
- Phyllosphere microbial community of cigar tobacco and its corresponding metabolites.
- Effect of Phosphoribosyltransferase Down-regulation on Malignant Glioma Cell Characteristics.
- Integrated Analysis of lncRNA and circRNA Mediated ceRNA Regulatory Networks in Skin Reveals Innate Immunity Differences Between Wild-Type and Yellow Mutant Rainbow Trout (Oncorhynchus mykiss).
- Identification of flux trade-offs in metabolic networks.
- Knockdown of Quinolinate Phosphoribosyltransferase Results in Decreased Salicylic Acid-Mediated Pathogen Resistance in Arabidopsis thaliana.
- Genetic evidence for Magnaporthe oryzae vitamin B3 acquisition from rice cells.
- Expression of a tobacco nicotine biosynthesis gene depends on the JRE4 transcription factor in heterogenous tomato.
- A network pharmacology-based approach to explore mechanism of action of medicinal herbs for alopecia treatment.
- Organ Co-Relationship in Tryptophan Metabolism and Factors That Govern the Biosynthesis of Nicotinamide from Tryptophan.
- Cloning and functional characterization of quinolinic acid phosphoribosyl transferase (QPT) gene of Nicotiana tabacum.
- The Ethanolic Extract of Lindera aggregata Modulates Gut Microbiota Dysbiosis and Alleviates Ethanol-Induced Acute Liver Inflammation and Oxidative Stress SIRT1/Nrf2/NF-κB Pathway.