ST6 Gal Sialyltransferase 1/ST6GAL1: ProductsST6GAL1 (beta-galactoside alpha-2-6 sialyl transferase 1; also alpha-2,6-ST) is a 47-49 kDa member of the glycosyltransferase 29 family of proteins. It is principally expressed in hepatocytes, placenta and skeletal muscle, and may be unique in its ability to generate Sia-alpha-2, 6-Gal structures on liver proteins. Human ST6GAL1 is a 406 amino acid (aa) type II transmembrane protein that resides in Golgi membranes. It contains a short cytoplasmic segment (aa 1-9) and an extended luminal domain (aa 27-406) that possesses a phosphorylation site at Tyr369. ST6GAL1 undergoes BACE1-mediated cleavage to generate a 364 aa, 52-53 kDa soluble form. This acts within the Golgi lumen to glycosylate proteins destined for secretion. There is one potential alternative start site at Met232. Over aa 27-406, human ST6GAL1 shares 75% aa identity with mouse ST6GAL1.