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 .
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].
termination by boiling for 60 seconds, analysis by thin layer chromatography (radiolabeled nicotinic acid) or ESI-MS, no NaMN detectable in Hep-G2 cells
-
r
nicotinate + 5-phospho-alpha-D-ribose 1-diphosphate + ATP + H2O
enzyme is able to generate adenosine 5'-tetraphosphate using substrate ATP and product phosphate, reaction of EC 3.6.1.14. Accompanying a typically irreversible hydrolysis of ATP to ADP and phosphate, is a fully reversible phosphate transfer reaction between ATP and adenosine 5'-tetraphosphate
not inhibitory: FK866. NaPRTase acks a tunnel that, in nicotinamide phosphoribosiltransferase EC 2.4.2.12, represents the binding site of inhibitor FK866
not inhibitory: FK866. NaPRTase acks a tunnel that, in nicotinamide phosphoribosiltransferase EC 2.4.2.12, represents the binding site of inhibitor FK866
Inhibition of nicotinamide phosphoribosyltransferase (NAMPT) activity by small molecule GMX1778 regulates reactive oxygen species (ROS)-mediated cytotoxicity in a p53- and nicotinic acid phosphoribosyltransferase1 (NAPRT1)-dependent manner.
The small molecule GMX1778 is a potent inhibitor of NAD+ biosynthesis: strategy for enhanced therapy in nicotinic acid phosphoribosyltransferase 1-deficient tumors.
Tissue-specific regulation of sirtuin and nicotinamide adenine dinucleotide biosynthetic pathways identified in C57Bl/6 mice in response to high-fat feeding.
A preclinical study on the rescue of normal tissue by nicotinic acid in high-dose treatment with APO866, a specific nicotinamide phosphoribosyltransferase inhibitor.
Inhibition of nicotinamide phosphoribosyltransferase (NAMPT) activity by small molecule GMX1778 regulates reactive oxygen species (ROS)-mediated cytotoxicity in a p53- and nicotinic acid phosphoribosyltransferase1 (NAPRT1)-dependent manner.
The small molecule GMX1778 is a potent inhibitor of NAD+ biosynthesis: strategy for enhanced therapy in nicotinic acid phosphoribosyltransferase 1-deficient tumors.
Inhibition of nicotinamide phosphoribosyltransferase (NAMPT) activity by small molecule GMX1778 regulates reactive oxygen species (ROS)-mediated cytotoxicity in a p53- and nicotinic acid phosphoribosyltransferase1 (NAPRT1)-dependent manner.
The small molecule GMX1778 is a potent inhibitor of NAD+ biosynthesis: strategy for enhanced therapy in nicotinic acid phosphoribosyltransferase 1-deficient tumors.
The small molecule GMX1778 is a potent inhibitor of NAD+ biosynthesis: strategy for enhanced therapy in nicotinic acid phosphoribosyltransferase 1-deficient tumors.
Inhibition of nicotinamide phosphoribosyltransferase (NAMPT) activity by small molecule GMX1778 regulates reactive oxygen species (ROS)-mediated cytotoxicity in a p53- and nicotinic acid phosphoribosyltransferase1 (NAPRT1)-dependent manner.
The small molecule GMX1778 is a potent inhibitor of NAD+ biosynthesis: strategy for enhanced therapy in nicotinic acid phosphoribosyltransferase 1-deficient tumors.
+/-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
+/-0.0016 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
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
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
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
Please wait a moment until the data is sorted. This message will disappear when the data is sorted.
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
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
Please wait a moment until the data is sorted. This message will disappear when the data is sorted.
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
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
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