Any feedback?
Please rate this page
(enzyme.php)
(0/150)

BRENDA support

BRENDA Home
show all | hide all No of entries

Information on EC 6.3.4.21 - nicotinate phosphoribosyltransferase and Organism(s) Homo sapiens and UniProt Accession Q6XQN6

for references in articles please use BRENDA:EC6.3.4.21
Please wait a moment until all data is loaded. This message will disappear when all data is loaded.
EC Tree
     6 Ligases
         6.3 Forming carbon-nitrogen bonds
             6.3.4 Other carbon-nitrogen ligases
                6.3.4.21 nicotinate phosphoribosyltransferase
IUBMB Comments
The enzyme, which is involved in pyridine nucleotide recycling, can form beta-nicotinate D-ribonucleotide and diphosphate from nicotinate and 5-phospho-alpha-D-ribose 1-diphosphate (PRPP) in the absence of ATP. However, when ATP is available the enzyme is phosphorylated resulting in a much lower Km for nicotinate. The phospho-enzyme is hydrolysed during the transferase reaction, regenerating the low affinity form. The presence of ATP shifts the products/substrates equilibrium from 0.67 to 1100 .
Specify your search results
Select one or more organisms in this record: ?
This record set is specific for:
Homo sapiens
UNIPROT: Q6XQN6
Show additional data
Do not include text mining results
Include (text mining) results
Include results (AMENDA + additional results, but less precise)
Word Map
The taxonomic range for the selected organisms is: Homo sapiens
The enzyme appears in selected viruses and cellular organisms
Synonyms
nicotinic acid phosphoribosyltransferase, nicotinate phosphoribosyltransferase, naprtase, naprt1, na phosphoribosyltransferase, more
SYNONYM
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
NA phosphoribosyltransferase
-
nicotinate phosphoribosyltransferase
-
nicotinic acid phosphoribosyltransferase
-
niacin ribonucleotidase
-
-
-
-
nicotinate-nucleotide:pyrophosphate phospho-alpha-D-ribosyltransferase
-
-
-
-
nicotinic acid mononucleotide glycohydrolase
-
-
-
-
REACTION TYPE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
pentosyl group transfer
-
pentosyl group transfer
-
-
-
-
PATHWAY SOURCE
PATHWAYS
-
-, -, -
SYSTEMATIC NAME
IUBMB Comments
5-phospho-alpha-D-ribose 1-diphosphate:nicotinate ligase (ADP, diphosphate-forming)
The enzyme, which is involved in pyridine nucleotide recycling, can form beta-nicotinate D-ribonucleotide and diphosphate from nicotinate and 5-phospho-alpha-D-ribose 1-diphosphate (PRPP) in the absence of ATP. However, when ATP is available the enzyme is phosphorylated resulting in a much lower Km for nicotinate. The phospho-enzyme is hydrolysed during the transferase reaction, regenerating the low affinity form. The presence of ATP shifts the products/substrates equilibrium from 0.67 to 1100 [4].
CAS REGISTRY NUMBER
COMMENTARY hide
9030-26-6
-
SUBSTRATE
PRODUCT                       
REACTION DIAGRAM
ORGANISM
UNIPROT
COMMENTARY
(Substrate) hide
LITERATURE
(Substrate)
COMMENTARY
(Product) hide
LITERATURE
(Product)
Reversibility
r=reversible
ir=irreversible
?=not specified
nicotinate + 5-phospho-alpha-D-ribose 1-diphosphate + ATP + H2O
beta-nicotinate D-ribonucleotide + diphosphate + ADP + phosphate
show the reaction diagram
nicotinate + 5-phospho-alpha-D-ribose 1-diphosphate + ATP + H2O
beta-nicotinate D-ribonucleotide + diphosphate + ADP + phosphate
show the reaction diagram
additional information
?
-
NATURAL SUBSTRATE
NATURAL PRODUCT
REACTION DIAGRAM
ORGANISM
UNIPROT
COMMENTARY
(Substrate) hide
LITERATURE
(Substrate)
COMMENTARY
(Product) hide
LITERATURE
(Product)
REVERSIBILITY
r=reversible
ir=irreversible
?=not specified
nicotinate + 5-phospho-alpha-D-ribose 1-diphosphate + ATP + H2O
beta-nicotinate D-ribonucleotide + diphosphate + ADP + phosphate
show the reaction diagram
nicotinate + 5-phospho-alpha-D-ribose 1-diphosphate + ATP + H2O
beta-nicotinate D-ribonucleotide + diphosphate + ADP + phosphate
show the reaction diagram
COFACTOR
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
METALS and IONS
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
INHIBITOR
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
2-hydroxynicotinic acid
-
acetyl-CoA
at 1 mM 40% inhibition of activity (concentrations of substrates 1 mM)
ATP
at high substrate saturation
CoA
at 1 mM 70% inhibition of activity (concentrations of substrates 1 mM)
D-fructose 1,6-bisphosphate
at 1 mM 36% inhibition of activity (concentrations of substrates 1 mM)
glutaryl-CoA
at 1 mM 42% inhibition of activity (concentrations of substrates 1 mM)
glyceraldehyde 3-phosphate
at 1 mM 27% inhibition of activity (concentrations of substrates 1 mM)
phosphoenolpyruvate
at 1 mM 33% inhibition of activity (concentrations of substrates 1 mM)
succinyl-CoA
at 1 mM 53% inhibition of activity (concentrations of substrates 1 mM)
Nicotinate analogues
-
-
-
additional information
-
ACTIVATING COMPOUND
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
ATP
at low substrate saturation (below 0,1 mM)
KM VALUE [mM]
SUBSTRATE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
0.00022 - 0.0382
5-phospho-alpha-D-ribose 1-diphosphate
0.0273 - 0.0443
nicotinate
0.0127 - 0.0155
nicotinic acid
0.06 - 0.1
5-phospho-alpha-D-ribose 1-diphosphate
0.0005 - 0.024
nicotinate
TURNOVER NUMBER [1/s]
SUBSTRATE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
0.01 - 0.36
5-phospho-alpha-D-ribose 1-diphosphate
0.012 - 0.25
nicotinate
kcat/KM VALUE [1/mMs-1]
SUBSTRATE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
0.452 - 9.42
5-phospho-alpha-D-ribose 1-diphosphate
0.271 - 9.16
nicotinate
IC50 VALUE [mM]
INHIBITOR
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
0.85
CoA
Homo sapiens
pH 7.5, 37°C
SPECIFIC ACTIVITY [µmol/min/mg]
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
0.0169
+/-0.006 micromol/min/mg, with respect to nicotinic acid, in presence of 1 mM NAD+, 80 ng enzyme, 10-70 microM nicotinamide, 0.3 mM PRPP, 30 min, 37°C, TLC-based quantification
0.0186
+/-0.006 micromol/min/mg, with respect to nicotinic acid, 80 ng enzyme, 10-70 microM nicotinamide, 0.3 mM PRPP, 30 min, 37°C, TLC-based quantification
0.0226
+/-0.0016 micromol/min/mg, with respect to 5-phospho-alpha-D-ribose 1-diphosphate, in presence of 1 mM NAD+, 20 ng enzyme, 40 microM nicotinamide, 0.14-1 microM PRPP, 15 min, 37°C, TLC-based quantification
0.0236
+/-0.0015 micromol/min/mg, with respect to 5-phospho-alpha-D-ribose 1-diphosphate, 20 ng enzyme, 40 microM nicotinamide, 0.14-1 microM PRPP, 15 min, 37°C, TLC-based quantification
0.052
-
-
pH OPTIMUM
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
6.5 - 8
-
broad, 0.2 M potassium phosphate buffer or 0.05 M Tris-Cl
TEMPERATURE OPTIMUM
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
37
-
assay at
ORGANISM
COMMENTARY hide
LITERATURE
UNIPROT
SEQUENCE DB
SOURCE
-
SwissProt
Manually annotated by BRENDA team
SOURCE TISSUE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
SOURCE
exogenously added nicotinic acid (1-10 microM) leads to increase in basal total NAD++ level (revealed by ESI-MS) in a dose-dependent manner and to NaAD+ accumulation which are reduced by siRNA-based knock-down of endogenous NAPRT, knock-down does not affect basal NAD++ levels (503 +/-104 microM) in absence of exogenous nicotinic acid, exogenously added nicotinic acid decreases oxidative cytotoxicity (by 30-50 microM hydrogen peroxide) through elevated NAD+ levels mediated by NAPRT activity as revealed by siRNA-based knock-down of NAPRT
Manually annotated by BRENDA team
very low protein expression level (mouse polyclonal anti-human NAPRT antibody) and enzymatic activity (TLC)
Manually annotated by BRENDA team
-
weak expression
Manually annotated by BRENDA team
-
weak expression
Manually annotated by BRENDA team
-
weak expression
Manually annotated by BRENDA team
-
weak expression
Manually annotated by BRENDA team
additional information
-
gene is ubiquitously expressed at the mRNA level in all normal human tissues tested. No expression MKN-28 cell
Manually annotated by BRENDA team
LOCALIZATION
ORGANISM
UNIPROT
COMMENTARY hide
GeneOntology No.
LITERATURE
SOURCE
GENERAL INFORMATION
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
physiological function
both NAPRT and nicotinamide phosphoribosyltransferase NAMPT increase intracellular NAD+ levels. NAPRT silencing reduces energy status, protein synthesis, and cell size in ovarian and pancreatic cancer cells. NAPRT silencing sensitizes cells to NAMPT inhibitors both in vitro and in vivo
UNIPROT
ENTRY NAME
ORGANISM
NO. OF AA
NO. OF TRANSM. HELICES
MOLECULAR WEIGHT[Da]
SOURCE
SEQUENCE
LOCALIZATION PREDICTION?
PNCB_HUMAN
538
0
57578
Swiss-Prot
other Location (Reliability: 2)
PDB
SCOP
CATH
UNIPROT
ORGANISM
MOLECULAR WEIGHT
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
110000
non-denaturing polyacrylamide gel electrophoresis of purified recombinant NAPRT in active state as controlled by applying gel slice to TLC-based activity assay with 50 microM nicotinic acid + 0.3 mM PRPP, 3 h, 37°C
51000
endogenous NAPRT detected in Western blot using mouse polyclonal anti-human NAPRT antibody
52000
overexpressed, His-tagged NAPRT in Hep-G2 cells detected in Western blot using mouse polyclonal anti-human NAPRT antibody
54000
purified recombinant NAPRT
55000
2 * 55000, non-denaturing polyacrylamide gel electrophoresis of purified recombinant NAPRT in active state
59800
calculated from the deduced protein sequence
87000
gel filtration, predicted value of monomer: 59249 Da
86000
-
gel filtration
SUBUNIT
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
homodimer
2 * 55000, non-denaturing polyacrylamide gel electrophoresis of purified recombinant NAPRT in active state
CRYSTALLIZATION (Commentary)
ORGANISM
UNIPROT
LITERATURE
by molecular replacement at a resolution of 2.9 A, in its ligand-free form. The enzyme consists of two domains and functions as a dimer with the active site located at the interface of the monomers. NaPRTase acks a tunnel that, in nicotinamide phosphoribosyltransferase EC 2.4.2.12, represents the binding site of inhibitor FK866
PROTEIN VARIANTS
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
D19A
activity completely abolished
D288A
about 10% of wild type activity
G169A
about 40% of wild type activity
G209A
about 20% of wild type activity
G379A
activity completely abolished
H213A
about 50% of wild type activity
N357A
about 80% of wild type activity
R318A
activity strictly dependent on the presence of ATP
S381A
about 40% of wild type activity
T380A
about 50% of wild type activity
Y21A
activity strictly dependent on the presence of ATP
H213A
-
mutant is unable to generate adenosine 5'-tetraphosphate
pH STABILITY
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
5 - 10
-
stable, 0.2 M potassium phosphate buffer
637752
GENERAL STABILITY
ORGANISM
UNIPROT
LITERATURE
50% activity recovered at salt concentrations of 50 mM, inactivation with salt concentrations below 20 mM, 20-35% glycerol partially protects
-
glycerol, 20-35%, stabilizes during dialysis against low buffer concentrations, more highly purified preparations require higher glycerol concentrations
-
STORAGE STABILITY
ORGANISM
UNIPROT
LITERATURE
-70°C, t1/2: 3 months
-
-70ºC, no significantly decreased activity for up to 3 years, no significantly decreased after 8 years
-
PURIFICATION (Commentary)
ORGANISM
UNIPROT
LITERATURE
immobilized metal ion affinity chromatography (Ni2+)
nickel chelate His-bind resin after bacterial expression
ammonium sulfate fractionation, chromatography on DEAE-cellulose, chromatography on Sephadex, affinity column chromatography and hydroxylapatite column chromatography, 30000fold purified
-
heparinised blood lysates
-
CLONED (Commentary)
ORGANISM
UNIPROT
LITERATURE
expression in Escherichia coli as His6-tagged protein
His-tagged protein expressed in Escherichia coli BL21
in pET22b and pET15b for expression in Escherichia coli BL21 (DE3) as fusion protein with C-terminal or N-terminal hexa-His-tag, respectively, in pcDNA3His(6) for expression in eukaryotic cell culture, specific siRNAs against nt829-1634 and nt445-935 for transfection into HEK-293 cells
EXPRESSION
ORGANISM
UNIPROT
LITERATURE
presence of more than one NAPRT transcript in most tissues, all with identical 3' end sequence. Some NAPRT transcripts appear to be tissuespecific. Brain shows the highest number of alternative transcripts. Several modulators of the NAPRT gene expression are involved, i.e. mutations in transcription factor binding sites, promoter methylation and alternative splicing
-
APPLICATION
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
medicine
NAPRT is amplified and overexpressed in a subset of common types of cancer, including ovarian cancer, where NAPRT expression correlates with a BRCAness gene expression signature. Both NAPRT and nicotinamide phosphoribosyltransferase NAMPT increase intracellular NAD+ levels. NAPRT silencing reduces energy status, protein synthesis, and cell size in ovarian and pancreatic cancer cells. NAPRT silencing sensitizes cells to NAMPT inhibitors both in vitro and in vivo. Reducing NAPRT levels in a BRCA2-deficient cancer cell line exacerbates DNA damage in response to chemotherapeutics
REF.
AUTHORS
TITLE
JOURNAL
VOL.
PAGES
YEAR
ORGANISM (UNIPROT)
PUBMED ID
SOURCE
Gaut, Z.N.; Solomon, H.M.
Inhibition of nicotinate phosphoribosyltransferase in human platelet lysate by nicotinic acid analogs
Biochem. Pharmacol.
20
2903-2906
1971
Homo sapiens
Manually annotated by BRENDA team
Niedel, J.; Dietrich, L.S.
Nicotinate phosphoribosyltransferase of human erythrocytes. Purification and properties
J. Biol. Chem.
248
3500-3505
1973
Homo sapiens
Manually annotated by BRENDA team
Pescaglini, M.; Micheli, V.; Simmonds, H.A.; Rocchigiani, M.; Pompucci, G.
Nicotinic acid phosphoribosyltransferase activity in human erythtocytes: studies using a niw HPLC method
Clin. Chim. Acta
229
15-25
1994
Homo sapiens
Manually annotated by BRENDA team
Hara, N.; Yamada, K.; Shibata, T.; Osago, H.; Hashimoto, T.; Tsuchiya, M.
Elevation of cellular NAD levels by nicotinic acid and involvement of nicotinic acid phosphoribosyltransferase in human cells
J. Biol. Chem.
282
24574-24582
2007
Mus musculus, Mus musculus (Q8CC86), Rattus norvegicus (Q6XQN1), Homo sapiens (Q6XQN6), Homo sapiens, Mus musculus BALB/c (Q8CC86)
Manually annotated by BRENDA team
Galassi, L.; Di Stefano, M.; Brunetti, L.; Orsomando, G.; Amici, A.; Ruggieri, S.; Magni, G.
Characterization of human nicotinate phosphoribosyltransferase: Kinetic studies, structure prediction and functional analysis by site-directed mutagenesis
Biochimie
94
300-309
2012
Homo sapiens (Q6XQN6), Homo sapiens
Manually annotated by BRENDA team
Piacente, F.; Caffa, I.; Ravera, S.; Sociali, G.; Passalacqua, M.; Vellone, V.G.; Becherini, P.; Reverberi, D.; Monacelli, F.; Ballestrero, A.; Odetti, P.; Cagnetta, A.; Cea, M.; Nahimana, A.; Duchosal, M.; Bruzzone, S.; Nencioni, A.
Nicotinic acid phosphoribosyltransferase regulates cancer cell metabolism, susceptibility to NAMPT inhibitors, and DNA repair
Cancer Res.
77
3857-3869
2017
Homo sapiens (Q6XQN6)
Manually annotated by BRENDA team
Amici, A.; Grolla, A.A.; Del Grosso, E.; Bellini, R.; Bianchi, M.; Travelli, C.; Garavaglia, S.; Sorci, L.; Raffaelli, N.; Ruggieri, S.; Genazzani, A.A.; Orsomando, G.
Synthesis and degradation of adenosine 5-tetraphosphate by nicotinamide and nicotinate phosphoribosyltransferases
Cell Chem. Biol.
24
553-564
2017
Homo sapiens
Manually annotated by BRENDA team
Marletta, A.S.; Massarotti, A.; Orsomando, G.; Magni, G.; Rizzi, M.; Garavaglia, S.
Crystal structure of human nicotinic acid phosphoribosyltransferase
FEBS open bio
5
419-428
2015
Homo sapiens (Q6XQN6), Homo sapiens
Manually annotated by BRENDA team
Duarte-Pereira, S.; Pereira-Castro, I.; Silva, S.S.; Correia, M.G.; Neto, C.; da Costa, L.T.; Amorim, A.; Silva, R.M.
Extensive regulation of nicotinate phosphoribosyltransferase (NAPRT) expression in human tissues and tumors
Oncotarget
7
1973-1983
2016
Homo sapiens
Manually annotated by BRENDA team