PBEF/Visfatin: Proteins and Enzymes

PBEF, also called Nampt or visfatin, is a ubiquitous 52 kDa nicotinamide phosphoribosyltransferase. PBEF is the rate-limiting component in the biosynthesis of NAD+, and functions in the cytoplasm to regulate energy metabolism during stress responses and immune activation. Although it lacks a signal sequence, PBEF appears to be secreted by visceral adipose and functions as a noncompetitive insulin mimetic. Mouse PBEF shows 96% and > 99% aa identity with human and rat PBEF, respectively.