B4galt1 (human) recombinant (partia l protein gst tag) 25 µg

This gene is one of 7 b4GalT genes. They encode type II memb-bound glycopr that appear to have exclusive specificity for donor substrate UDP-galactose; all transfer galactose in a b1,4 linkage to similar acceptor sugars: GlcNAc, Glc, and Xyl. Each b4GalT has a distinct function in biosynthesis of different glycoconjugates and saccharide strs. As type II memb pr., they have an N-terminal hydrophobic signal seq that directs pr. to Golgi apparatus which remains uncleaved to function as a transmembrane anchor. By seq similarity, b4GalTs form 4 gps: b4GalT1 and b4GalT2, b4GalT3 and b4GalT4, b4GalT5 and b4GalT6, b4GalT7. This gene is unique among b4GalT genes because it encodes an enzyme that participates both in glycoconjugate and lactose biosynthesis. For first activity, enzyme adds galactose to N-acetylglucosamine residues that are either monosaccharides or nonreducing ends of glycoprotein carbohydrate chains. 2nd activity is restricted to lactating mammary tissues where enzyme forms a heterodimer with a-lactalbumin to catalyze UDP-galactose + D-glucose = UDP + lactose. two enzymatic forms result from alternate transcription initiation sites and post-translational processing. 2 transcripts, which differ only at 5' end, with app. lengths of 4.1kb and 3.9kb encode same pr. longer transcript encodes type II mem-bound, trans-Golgi resident pr. involved in glycoconjugate biosynthesis. The shorter transcript encodes a pr which is cleaved to form soluble lactose synthase.