| 摘要 |
A novel gene defining a novel enzyme in the UDP-D-galactose: .beta.-N- acetylglucosamine/.beta.-N-acetylgalactosamine .beta.1,3galactosyltransferas e family, termed .beta.3Gal-T5, with unique enzymatic properties is disclosed. The enzymatic activity of .beta.3Gal-T5 is shown to be distinct from that of previously identified enzymes of this gene family. The invention discloses isolated DNA molecules and DNA constructs encoding .beta.3Gal-T5 and derivatives thereof by way of amino acid deletion, substitution or insertion exhibiting .beta.3Gal-T5 activity, as well as cloning and expression vectors including such DNA, cells tranfected with the vectors, and recombinant metho ds for providing .beta.3Gal-T5. The enzyme .beta.3Gal-T5 and .beta.3Gal-T5-acti ve derivatives thereof are disclosed, in particular soluble derivatives comprising the catalytically active domain of .beta.3Gal-T5. Further, the invention discloses methods of obtaining .beta.1,3galactosyl glycosylated saccharides, glycopeptides or glycoproteins by use of an enzymically active .beta.3Gal-T5 protein or fusion protein thereof or by using cells stably transfected with a vector including DNA encoding an enzymatically active .beta.3Gal-T5 protein as an expression system for recombinant production of such glycopeptides or glycoproteins.Also a method for the identification of DNA sequence variations in the .beta.3Gal-T5 gene by isolating DNA from a patient, amplifying .beta.3Gal-T5-coding exons by PCR, and detecting the presence of DNA sequence variation, are disclosed.
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