Sialic acid molecules attached to glycoproteins or glycosphingolipids play important roles in various biological processes such as immune recognition, pathogen infection, and cell adhesion. Sialyltransferases are key enzymes that regulate the serum levels of sialic acid-containing molecules. Alpha-N-acetylgalactosaminide a-2,6-sialyltransferase 2, encoded by the ST6GALNAC2 gene, is a type II membrane protein localized in the Golgi network and catalyzes 2,6-sialylation of the Tn antigen (GalNAc-O-Ser/Thr) (1). Sialyl-Tn antigen is highly expressed in several human carcinomas and is associated with carcinoma aggressiveness and poor prognosis. Cells transfected with ST6GALNAC2 synthesized the sialyl-6T structure [GalB1-3 (Neu5Aca2-6) GalNAc-O-Ser/Thr] (2). In vitro analysis revealed that the enzyme can use both GalB1-3GalNAc and Neu5Aca2-3GalB1-3GalNAc as acceptor substrates (3). Recently, it has been reported that disregulation of this gene is involved in the pathogenesis of IgA nephropathy, a common kidney disease that occurs when antibody IgA accumulates in kidneys (4). The enzyme may also be used to synthesize a cancer vaccine (5, 6). At the protein level, mouse ST6GALNAC2 shows 75 sequence identity with the human homologue. The activity of this enzyme has been measured using a phosphatase-coupled assay (7). Source: Recombinant corresponding to aa28-373 from mouse ST6GALNAC2, fused with 6-His tag at C-terminal and human CD33 signal sequence at N-terminal, expressed in myeloma cell line, NSO cells. Molecular Weight: ~40kD Endotoxin Level: 1EU/1ug (LAL) Biological Activity: Measured by its ability to transfer Neu5Ac from CMP-Neu5Ac to bovine asialofetuin. Specific Activity: >225pmoles/min/ug, as measured under the described conditions. Storage and Stability: Aliquot to avoid repeated freezing and thawing and store at -70C. Aliquots are stable for at least 6 months. For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap.
