MISC

1996年

Acceptor substrate specificity of a cloned G(D3) synthase that catalyzes the biosynthesis of both G(D3) and G(D1c)/G(T1a)/G(Q1b)

European Journal of Biochemistry
  • Kiyomitsu Nara
  • ,
  • Yumiko Watanabe
  • ,
  • Ikuo Kawashima
  • ,
  • Tadashi Tai
  • ,
  • Yoshitaka Nagai
  • ,
  • Yutaka Sanai

238
3
開始ページ
647
終了ページ
652
記述言語
英語
掲載種別
DOI
10.1111/j.1432-1033.1996.0647w.x
出版者・発行元
Blackwell Publishing Ltd

To address the role of α2,8-sialyltransferase (G(D3) synthase) in the biosynthesis of gangliosides, we examined the substrate specificity of the enzyme. In the ganglioside synthesis pathway, it has been generally accepted that sialyltransferase II (SAT II) catalyzes the production of G(D3) from G(M3), and sialyltransferase V (SAT V) catalyzes the production of G(D1c)/G(T1a)/G(Q1b) from G(M1b)/G(D1a)/G(T1b). However, acceptor specificity of the cloned G(D3) synthase that was isolated from human melanoma cells [Nara, K., Watanabe, Y., Maruyama, K., Kasahara, K., Nagai, Y. and Sanai, Y. (1994) Proc. Natl. Acad. Sci. USA 91, 7952-7956] has revealed that this enzyme utilized the gangliosides containing the terminal Sia(α2-3)Gal structure of the carbohydrate moiety, which includes G(M3), G(M1b), G(D1a), and G(T1b) as exogenous substrates. Kinetic data also showed that the enzyme was able to utilize both G(M1), and G(M1b)/G(D1a)/G(T1b) as acceptor substrates. These data indicate that the enzyme catalyzes the formation of not only G(D3) but also G(D1c), G(I1a), and G(Q1b) in vitro. Furthermore, by transfection of the cloned human α2,8-sialyltransferase cDNA, transient and stable expression of G(T1a) and G(Q1b) was also observed in COS-7 cells and Swiss 3T3 cells that originally lacked SAT II and SAT V activities. These observations indicate that the enzyme has both SAT II and SAT V activities in vivo.

リンク情報
DOI
https://doi.org/10.1111/j.1432-1033.1996.0647w.x
PubMed
https://www.ncbi.nlm.nih.gov/pubmed/8706663
ID情報
  • DOI : 10.1111/j.1432-1033.1996.0647w.x
  • ISSN : 0014-2956
  • PubMed ID : 8706663
  • SCOPUS ID : 0030056086

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