Recombinant Human PBEF/Visfatin Protein, CF

PBEF, also called Visfatin and NAMPT, is a dimeric type II phosphoribosyltransferase (1). It was initially identified as a secreted cytokine that synergized with IL-7 and SCF to stimulate early stage B cells (2). Human PBEF is predominantly expressed in bone marrow, liver, and muscle, with lower levels found in placenta, kidney, heart, and lung (2). Human PBEF shares 96% and 95% amino acid sequence identity with mouse and rat PBEF, respectively. PBEF has been identified both as an intracellular and as an extracellular protein. Within the cell, PBEF converts nicotinamide to nicotinamide mononucleotide (NMN), which is the rate limiting step in the production of nicotinamide adenine dinucleotide (NAD⁺) (3, 4). In the extracellular environment, PBEF has been reported to increase the production of inflammatory cytokines and have an important role in the development of T and B cells (5-7). Additionally, PBEF may promote angiogenesis in vivo in an ERK1/2-dependent manner (8). PBEF has been implicated in several inflammatory diseases, including rheumatoid arthritis, osteoarthritis, inflammatory bowel disease, and sepsis (9). PBEF over-expression has been observed in many cancer types (10).