Galanin: Proteins and Enzymes

Galanin (Glycine-Alanine, representing the N-and C-terminal amino acids in bovine Galanin; also GAL) is a 3 kDa (predicted), secreted member of the Galanin family of peptides. It is co-expressed with differing neuropeptides in a variety of neuron cell types. Galanin affects multiple metabolic processes by binding to one of three GPCRs. GalR1 blocks insulin secretion, GalR2 initiates neurogenesis and GalR3 influences addictive behavior. The human Galanin proform is 11-12 kDa in size (predicted) and 104 amino acids (aa) in length. Proteolytic processing generates a 30 aa mature Galanin peptide (aa 33-62), plus a phosphorylated (Ser117), C-terminal 59 aa GMAP fragment that is apparently involved in the processing of noxious stimuli. Once secreted, Galanin can undergo additional proteolytic degradation. Over aa 2-123, the human Galanin proform shares 72% aa identity with mouse Galanin proform.