Nicotinamide phosphoribosyltransferase (Nampt) is a rate-limiting enzyme in the mammalian NAD+ biosynthesis of a salvage pathway and exists in 2 known forms. intracellular Nampt (iNampt) and a secreted form. extracellular Nampt (eNampt). eNampt can generate an intermediate product. https://www.mariameetsanna.com/product-category/re-works/