Moriyasu M, Ito A
J Biochem. 1982 Oct;92(4):1197-204. doi: 10.1093/oxfordjournals.jbchem.a134036.
The intramembranous disposition of arylsulfatase C [EC 3.1.6.1] was studied. The lack of stimulation by Triton X-100 of microsomal arylsulfatase C activity indicated the outside location of the active site of the enzyme in microsomal vesicles. The exposure of arylsulfatase C on the surface of microsomal vesicles was also suggested by the binding of antibodies against the purified enzyme to intact microsomes. However, larger amounts of the antibodies were bound to microsomes in the presence of a low concentration of Triton X-100, suggesting the presence of other antigenic sites of the enzyme not available to the antibodies in intact microsomes. The treatment of solubilized and microsome-bound arylsulfatase C with transglutaminase indicated two susceptible glutamine residues per subunit of the enzyme molecule. One of the glutamine residues was labeled with transglutaminase in intact microsomes, whereas the other one became available to transglutaminase only after the addition of Triton X-100 to microsomes. These observations suggested that endoglycosidase H-sensitive carbohydrate chains of arylsulfatase C are located in the lumen of microsomal vesicles. We conclude that microsomal arylsulfatase C is a transmembranous protein and exposed on both outer and inner surfaces of the membrane.
对芳基硫酸酯酶C[EC 3.1.6.1]的膜内分布进行了研究。Triton X-100对微粒体芳基硫酸酯酶C活性缺乏刺激作用，表明该酶活性位点位于微粒体囊泡的外部。针对纯化酶的抗体与完整微粒体的结合也表明芳基硫酸酯酶C暴露于微粒体囊泡表面。然而，在低浓度Triton X-100存在下，更多量的抗体与微粒体结合，这表明该酶存在其他抗原位点，在完整微粒体中抗体无法识别这些位点。用转谷氨酰胺酶处理可溶的和与微粒体结合的芳基硫酸酯酶C，结果表明该酶分子每个亚基有两个易被作用的谷氨酰胺残基。其中一个谷氨酰胺残基在完整微粒体中被转谷氨酰胺酶标记，而另一个谷氨酰胺残基只有在向微粒体中加入Triton X-100后才会被转谷氨酰胺酶作用。这些观察结果表明，芳基硫酸酯酶C的内切糖苷酶H敏感型碳水化合物链位于微粒体囊泡腔内。我们得出结论，微粒体芳基硫酸酯酶C是一种跨膜蛋白，暴露于膜的外表面和内表面。
