EXPRESSION OF SOLUBLE ACTIVE HUMAN BETA-1,4 GALACTOSYLTRANSFERASE IN SACCHAROMYCES-CEREVISIAE

Sequences coding for the cytoplasmic and transmembrane domains were removed from the cDNA of the human Golgi resident membrane protein beta 1,4 galactosyltransferase (gal-T). The remaining sequences coding for the stem and catalytical domains of this glycosyltransferase were fused to sequences coding for the yeast invertase signal sequence. The hybrid was inserted together with a constitutive yeast promoter and a terminator into a E. coli/yeast shuttle vector. Saccharomyces cerevisiae strain BT150 transformed with this new expression vector expressed enzymically active soluble enzyme, whereas no activity was detectable in mock-transformed yeasts. The enzyme product was identified by HPLC analysis and shown to correspond to the expected product N-acetyllactosamine. (C) 1994 Academic Press, Inc.