Expression of human glycosyltransferase genes in yeast as a tool for enzymatic synthesis of sugar chain.

We planned the production of human glycosyltransferases in yeast for the enzymatic synthesis of various sugar chains. More than 160 genes encoding various glycosyltransferases were prepared as N-terminal transmembrane region truncated forms by PCR and were inserted into the entry vector of Invitrogen Ltd's Gateway system. About fifty glycosyltransferases were chosen for the synthesis of human type oligosaccharides, and expressed as two different forms in yeast. One is a soluble form, which is secreted into the culture medium by methylotrophic yeast, and the other is an immobilized form, which is displayed at the budding yeast cell wall as a fusion protein with Pir protein. To date, in both systems, some sialyltranferases and fucosyltransferases have been produced as active forms, indicating the potential usefulness of these systems for the enzymatic synthesis of various types of human sugar chains attached to proteins and lipids.