Nagai M, Davè V, Kaplan B E, Yoshida A
J Biol Chem. 1978 Jan 25;253(2):377-9.
An N-acetylgalactosaminyltransferase, which converts blood group O red blood cells to A cells, was purified to homogeneity from plasma of blood group A1 subjects. The enzyme was adsorbed on Sepharose 4B, and after washing out the impurities, the enzyme was eluted with UDP. This procedure resulted in a 70,000- to 100,000-fold increase in specific activity with recovery of about 80%. Further purification of the enzyme was achieved by Bio-Gel P treatment. The final enzyme preparation showed a single protein band, which coincided with enzyme activity, on acrylamide gel electrophoresis, and revealed a single protein band on sodium dodecyl sulfate-gel electrophoresis. Judging from the molecular weight (90,000 to 100,000), which was estimated by Sephadex gel filtration, and the subunit size estimated by sodium dodecyl sulfate-gel electrophoresis, the enzyme is presumably in a dimeric form. The enzyme required Mn2+ and had optimum activity at pH 6.5 to 7.0.
一种能将O型血红细胞转化为A型细胞的N - 乙酰半乳糖胺基转移酶从A1型血受试者的血浆中被纯化至同质。该酶吸附于琼脂糖4B上，洗去杂质后，用尿苷二磷酸（UDP）洗脱。此过程使比活性提高了70000至100000倍，回收率约为80%。通过生物凝胶P处理实现了该酶的进一步纯化。最终的酶制剂在丙烯酰胺凝胶电泳上显示出一条与酶活性一致的单一蛋白带，在十二烷基硫酸钠凝胶电泳上也显示出一条单一蛋白带。根据通过葡聚糖凝胶过滤估计的分子量（90000至100000）以及通过十二烷基硫酸钠凝胶电泳估计的亚基大小判断，该酶可能呈二聚体形式。该酶需要锰离子（Mn2+），在pH 6.5至7.0时具有最佳活性。
