黏蛋白合成。III. UDP-N-乙酰葡糖胺：半乳糖β1-3（N-乙酰葡糖胺β1-6）N-乙酰半乳糖胺-R（N-乙酰葡糖胺至半乳糖）β3-N-乙酰葡糖胺基转移酶，一种参与黏蛋白型寡糖延长的猪胃黏膜中的酶。
Mucin synthesis. III. UDP-GlcNAc:Gal beta 1-3(GlcNAc beta 1-6)GalNAc-R (GlcNAc to Gal) beta 3-N-acetylglucosaminyltransferase, an enzyme in porcine gastric mucosa involved in the elongation of mucin-type oligosaccharides.
作者信息
Brockhausen I, Williams D, Matta K L, Orr J, Schachter H
出版信息
Can J Biochem Cell Biol. 1983 Dec;61(12):1322-33. doi: 10.1139/o83-169.
Pig gastric mucosa microsomes have been shown to catalyze the following reaction: UDP-GlcNAc + Gal beta 1-3(GlcNAc beta 1-6)-GalNAc-alpha-R----GlcNAc beta 1-3Gal beta 1-3 (GlcNAc beta 1-6)GalNAc-alpha-R + UDP, where R is o-nitrophenyl or benzyl. The enzyme catalyzing this reaction has been named UDP-GlcNAc:Gal beta 1-3(GlcNAc beta 1-6)GalNAc-R (GlcNAc-R (GlcNAc to Gal) beta 3-N-acetylglucosaminyltransferase. The beta 3-GlcNAc-transferase does not act on Gal beta 1-3GalNAc-alpha-o-nitrophenyl. The beta 3-GlcNAc-transferase requires Mn2+ and Triton X-100 for optimal activity. The Vmax for the microsomal enzyme is 8.7 nmol/mg protein per hour and the Km values are 1.6, 0.9, and 1.2 mM for UDP-GlcNAc and the alpha-o-nitrophenyl and alpha-benzyl derivatives of Gal beta 1-3(GlcNAc beta 1-6)GalNAc, respectively. Pig gastric mucosa microsomes catalyze the transfer of GlcNAc to lactose to form GlcNAc beta 1-3Gal beta 1-4Glc, but fail to transfer GlcNAc to lactosyl ceramide, Gal beta 1-4GlcNAc, or Gal beta 1-4GlcNAc-beta-benzyl.
猪胃黏膜微粒体已被证明能催化以下反应
UDP - GlcNAc + Galβ1 - 3(GlcNAcβ1 - 6)-GalNAc - α - R→GlcNAcβ1 - 3Galβ1 - 3(GlcNAcβ1 - 6)GalNAc - α - R + UDP，其中R为邻硝基苯基或苄基。催化此反应的酶被命名为UDP - GlcNAc:Galβ1 - 3(GlcNAcβ1 - 6)GalNAc - R（GlcNAc - R（GlcNAc到Gal）β3 - N - 乙酰葡糖胺基转移酶）。β3 - GlcNAc转移酶对Galβ1 - 3GalNAc - α - 邻硝基苯基无作用。β3 - GlcNAc转移酶需要Mn2 +和Triton X - 100以达到最佳活性。微粒体酶的Vmax为每小时每毫克蛋白质8.7 nmol，UDP - GlcNAc以及Galβ1 - 3(GlcNAcβ1 - 6)GalNAc的α - 邻硝基苯基和α - 苄基衍生物的Km值分别为1.6、0.9和1.2 mM。猪胃黏膜微粒体催化将GlcNAc转移至乳糖形成GlcNAcβ1 - 3Galβ1 - 4Glc，但无法将GlcNAc转移至乳糖神经酰胺、Galβ1 - 4GlcNAc或Galβ1 - 4GlcNAc - β - 苄基。
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