Characterization of recombinant human glucuronyltransferase I involved in the biosynthesis of the glycosaminoglycan-protein linkage region of proteoglycans. |
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| Authors: | Y Tone H Kitagawa K Imiya S Oka T Kawasaki K Sugahara |
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| Institution: | Department of Biochemistry, Kobe Pharmaceutical University, 4-19-1 Motoyamakita-machi, Higashinada-ku, Kobe, Japan. |
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| Abstract: | We characterized the recombinant glucuronyltransferase I (GlcAT-I) involved in the glycosaminoglycan-protein linkage region biosynthesis. The enzyme showed strict specificity for Galbeta1-3Galbeta1-4Xyl, exhibiting negligible incorporation into other galactoside substrates including Galbeta1-3Galbeta1-O-benzyl, Galbeta1-4GlcNAc and Galbeta1-4Glc. A comparison of the GlcAT-I with another beta1,3-glucuronyltransferase involved in the HNK-1 epitope biosynthesis revealed that the two beta1,3-glucuronyltransferases exhibited distinct and no overlapping acceptor substrate specificities in vitro. Nevertheless, the transfection of the GlcAT-I cDNA into COS-1 cells induced the significant expression of the HNK-1 epitope. These results suggested that the high expression of the GlcAT-I gene rendered the cells capable of synthesizing the HNK-1 epitope. |
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