ST6GAL1 and cancer: In this work, we analyzed the contribution of solubility enhancer partners and the redox environment to the expression of functional disulfide bond containing human sialyltransferases ST3Gal1 and ST6Gal1 in E. coli. Activity of these enzymes is increased in different types of cancer,[2] and ST6Gal1 participates in the synthesis of core structure oligosaccharides of human milk oligosaccharides.