猪气管中两种不同的UDP-半乳糖：2-乙酰氨基-2-脱氧-D-葡萄糖4-β-半乳糖基转移酶

Two distinct UDP-galactose: 2-acetamido-2-deoxy-D-glucose 4 beta-galactosyltransferases in porcine trachea.

作者信息

Sheares B T, Carlson D M

出版信息

J Biol Chem. 1984 Jul 10;259(13):8045-7.

Abstract

In previous studies on glycosyltransferase activities in porcine trachea, we demonstrated the presence of two galactosyltransferases which transfer galactose from UDP-galactose to N-acetylglucosamine (Sheares, B.T. and Carlson, D.M. (1983) J. Biol. Chem. 258, 9893-9898). One enzyme, UDP-galactose:N-acetylglucosamine 3 beta-galactosyltransferase, synthesized galactosyl-beta 1,3-N-acetylglucosamine while the other, UDP-galactose:N-acetylglucosamine 4 beta-galactosyltransferase, synthesized galactosyl-beta 1,4-N-acetylglucosamine. A third galactosyltransferase has now been demonstrated utilizing a solubilized membrane preparation from pig trachea, which also synthesizes galactosyl-beta 1,4-N-acetylglucosamine as determined by gas-liquid chromatography and Diplococcus pneumoniae beta-galactosidase treatment. This new UDP-galactose:N-acetylglucosamine 4 beta-galactosyltransferase is distinct from the lactose synthetase A protein in that it does not bind to alpha-lactalbumin-agarose or to N-acetylglucosamine-agarose. The enzyme is separable from the UDP-galactose:N-acetylgalactosaminyl-mucin 3 beta-galactosyltransferase by affinity chromatography on asialo ovine submaxillary mucin adsorbed to DEAE-Sephacel. This newly discovered 4 beta-galactosyltransferase binds to UDP-hexanolamine-Sepharose and is partially separated from UDP-galactose:N-acetylglucosamine 3 beta-galactosyltransferase by Sephacryl S-200 gel filtration chromatography. Neither high concentrations of N-acetylglucosamine (200 mM) nor alpha-lactalbumin inhibits the incorporation of galactose into galactosyl-beta 1,4-N-acetylglucosamine by this enzyme.

摘要

在之前对猪气管中糖基转移酶活性的研究中，我们证明了存在两种半乳糖基转移酶，它们将半乳糖从UDP - 半乳糖转移至N - 乙酰葡糖胺（谢尔斯，B.T.和卡尔森，D.M.（1983年）《生物化学杂志》258卷，9893 - 9898页）。一种酶，UDP - 半乳糖：N - 乙酰葡糖胺3β - 半乳糖基转移酶，合成β1,3 - N - 乙酰葡糖胺半乳糖；而另一种，UDP - 半乳糖：N - 乙酰葡糖胺4β - 半乳糖基转移酶，合成β1,4 - N - 乙酰葡糖胺半乳糖。现在利用猪气管的可溶性膜制剂证明了第三种半乳糖基转移酶，通过气液色谱法和肺炎双球菌β - 半乳糖苷酶处理确定其也合成β1,4 - N - 乙酰葡糖胺半乳糖。这种新的UDP - 半乳糖：N - 乙酰葡糖胺4β - 半乳糖基转移酶与乳糖合成酶A蛋白不同，因为它不与α - 乳白蛋白 - 琼脂糖或N - 乙酰葡糖胺 - 琼脂糖结合。该酶可通过吸附于DEAE - 葡聚糖凝胶的去唾液酸羊下颌粘蛋白进行亲和层析，与UDP - 半乳糖：N - 乙酰半乳糖胺 - 粘蛋白3β - 半乳糖基转移酶分离。这种新发现的4β - 半乳糖基转移酶与UDP - 己醇胺 - 琼脂糖结合，并通过Sephacryl S - 200凝胶过滤层析与UDP - 半乳糖：N - 乙酰葡糖胺3β - 半乳糖基转移酶部分分离。高浓度的N - 乙酰葡糖胺（200 mM）和α - 乳白蛋白均不抑制该酶将半乳糖掺入β1,4 - N - 乙酰葡糖胺半乳糖中。