PBEF1 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. The protein is highly expressed in visceral fat and serum levels of the protein correlate with obesity. Synonyms: Monoclonal PBEF1 antibody, Anti-PBEF1 antibody, Pre-B-Cell Colony Enhancing Factor 1 antibody, 1110035O14Rik antibody, DKFZP666B131 antibody, MGC117256 antibody, NAMPT antibody, PBEF antibody.