Nicotinamide phosphoribosyltransferase

2E5B, 2E5C, 2E5D, 2GVG, 2GVJ, 3DGR, 3DHD, 3DHF, 3DKJ, 3DKL, 4JNM, 4JR5, 4KFN, 4KFO, 4KFP, 4L4L, 4L4M, 4LTS, 4LV9, 4LVA, 4LVB, 4LVD, 4LVF, 4LVG, 4LWW, 4M6P, 4M6Q, 4N9B, 4N9C, 4N9D, 4N9E, 4O0Z, 4O10, 4O12, 4O13, 4O14, 4O15, 4O16, 4O17, 4O18, 4O19, 4O1A, 4O1B, 4O1C, 4O1D, 4O28, 4WQ61013559027ENSG00000105835ENSMUSG00000020572P43490Q99KQ4NM_005746NM_182790NM_021524NP_005737NP_067499Nicotinamide phosphoribosyltransferase (NAmPRTase or Nampt) also known as pre-B-cell colony-enhancing factor 1 (PBEF1) or visfatin is an enzyme that in humans is encoded by the NAMPT gene. This protein is the rate-limiting enzyme in the Nicotinamide adenine dinucleotide (NAD+) salvage pathway that converts nicotinamide to nicotinamide mononucleotide in mammals to enable NAD+ biosynthesis. NAMPT has also been reported to be a cytokine (PBEF) that promotes B cell maturation and inhibits neutrophil apoptosis.2g95: Crystal Structure of Visfatin/Pre-B Cell Colony Enhancing Factor 1/Nicotinamide Phosphoribosyltransferase2g96: Crystal Structure of Visfatin/Pre-B Cell Colony Enhancing Factor 1/Nicotinamide Phosphoribosyltransferase In Complex with Niconamide Mononucleotide2g97: Crystal Structure of Visfatin/Pre-B Cell Colony Enhancing Factor 1/Nicotinamide Phosphoribosyltransferase In Complex with the Specific Inhibitor FK-8662gvg: Crystal Structure of human NMPRTase and its complex with NMN2gvj: Crystal Structure of Human NMPRTase in complex with FK8662gvl: Crystal Structure of Murine NMPRTase2h3b: Crystal Structure of Mouse Nicotinamide Phosphoribosyltransferase/Visfatin/Pre-B Cell Colony Enhancing Factor 12h3d: Crystal Structure of Mouse Nicotinamide Phosphoribosyltransferase/Visfatin/Pre-B Cell Colony Enhancing Factor in Complex with Nicotinamide Mononuleotide Nicotinamide phosphoribosyltransferase (NAmPRTase or Nampt) also known as pre-B-cell colony-enhancing factor 1 (PBEF1) or visfatin is an enzyme that in humans is encoded by the NAMPT gene. This protein is the rate-limiting enzyme in the Nicotinamide adenine dinucleotide (NAD+) salvage pathway that converts nicotinamide to nicotinamide mononucleotide in mammals to enable NAD+ biosynthesis. NAMPT has also been reported to be a cytokine (PBEF) that promotes B cell maturation and inhibits neutrophil apoptosis. NAMPT is downregulated by an increase of miR-34a in obesity via a 3'UTR functional binding site of NAMPT mRNA resulting in a reduction of NAD(+) and decreased SIRT1 activity. NAMPT catalyzes the following chemical reaction: Thus, the two substrates of this enzyme are nicotinamide and 5-phosphoribosyl-1-pyrophosphate (PRRP), whereas its two products are nicotinamide mononucleotide and pyrophosphate. This enzyme belongs to the family of glycosyltransferases, to be specific, the pentosyltransferases. This enzyme participates in nicotinate and nicotinamide metabolism. NAmPRTase catalyzes the condensation of nicotinamide with 5-phosphoribosyl-1-pyrophosphate to yield nicotinamide mononucleotide, one step in the biosynthesis of nicotinamide adenine dinucleotide. The protein is an adipokine that is localized to the bloodstream and has various functions, including the promotion of vascular smooth muscle cell maturation and inhibition of neutrophil apoptosis. It also activates insulin receptor and has insulin-mimetic effects, lowering blood glucose and improving insulin sensitivity. However, the paper was retracted in 2007. The protein is highly expressed in visceral fat and serum levels of the protein correlate with obesity. This gene has a pseudogene on chromosome 10. Recently, it has been demonstrated that NAMPT could bind to and activate TLR4. The systematic name of this enzyme class is nicotinamide-nucleotide:diphosphate phospho-alpha-D-ribosyltransferase. Other names in common use include: Nampt/PBEF/visfatin was originally cloned as a putative cytokine shown to enhance the maturation of B cell precursors in the presence of Interleukin-7 (IL-7) and stem cell factor, it was therefore named “pre-B cell colony-enhancing factor” (PBEF). When the gene encoding the bacterial nicotinamide phosphoribosyltransferase (nadV) was first isolated in Haemophilus ducreyi, it was found to exhibit significant homology to the mammalian PBEF gene. Rongvaux et al. demonstrated genetically that the mouse PBEF gene conferred Nampt enzymatic activity and NAD-independent growth to bacteria lacking nadV. Revollo et al. determined biochemically that the mouse PBEF gene product encodes a Nampt enzyme, capable of modulating intracellular NAD levels. Others have since confirmed these findings. More recently, several groups have reported the crystal structure of Nampt/PBEF/visfatin and they all show that this protein is a dimeric type II phosphoribosyltransferase enzyme involved in NAD biosynthesis.