Pfeiffer G, Strube K H, Geyer R
Institute of Biochemistry, University of Giessen, Germany.
Biochem Biophys Res Commun. 1992 Dec 30;189(3):1681-5. doi: 10.1016/0006-291x(92)90271-l.
Recombinant human tissue plasminogen activator expressed in murine epithelial cells carries, in part, sulfated N-glycans, which are characterized by the presence of a NeuAc alpha 3[SO4-6]Gal unit. In order to study the biosynthesis of this novel structural element, corresponding sulfated asialooligosaccharide alditols were resialylated in vitro using a crude sialyltransferase preparation from murine liver which was shown to contain Gal beta 1,3(4)GlcNAc alpha 2,3-sialyltransferase activity. Products were analyzed for transfer of sialic acid residues by anion-exchange HPLC. The results demonstrated that resialylation of SO4-6Gal-residues did not occur. Therefore, it may be concluded that transfer of the sulfate group is the final step in the biosynthesis of this structural epitope.
在鼠上皮细胞中表达的重组人组织型纤溶酶原激活剂部分带有硫酸化的N-聚糖，其特征在于存在NeuAcα3[SO4-6]Gal单元。为了研究这种新型结构元件的生物合成，使用来自鼠肝脏的粗制唾液酸转移酶制剂在体外对相应的硫酸化去唾液酸寡糖糖醇进行再唾液酸化，该制剂显示含有Galβ1,3(4)GlcNAcα2,3-唾液酸转移酶活性。通过阴离子交换HPLC分析产物中唾液酸残基的转移情况。结果表明，SO4-6Gal残基未发生再唾液酸化。因此，可以得出结论，硫酸基团的转移是该结构表位生物合成的最后一步。
