Drescher D G
Proc Natl Acad Sci U S A. 1977 Mar;74(3):892-6. doi: 10.1073/pnas.74.3.892.
A soluble carbonic anhydrase (carbonate hydro-lyase, EC 4.2.1.1) has been purified to homogeneity from the membranous lateral wall (stria vascularis, spiral ligament, spiral prominence, and outer sulcus) of the guinea-pig inner ear. About 1% of the protein of the membranous lateral wall is carbonic anhydrase. The specific activity of the enzyme in homogenates of the lateral wall is 1.6-1.8 times that of whole blood; for homogenates of the components, stria vascularis and the fraction containing the spiral ligament, the specific activities are 0.9 and 2.0 times the specific activity of whole blood, respectively. No other cochlear fraction examined contains appreciable carbonic anhydrase. The purified enzyme has a molecular weight of about 30,000, a specific activity 60--80% that of carbonic anhydrase C from blood, and an electrophoretic mobility similar to that of the blood enzyme. Cochlear carbonic anhydrase is half-maximally inhibited by 4 X 10(-9) M acetazolamide, is completely inhibited above 10(-5)M acetazolamide, and forms a fluorescent complex with 5-dimethylaminonaphthalene-1-sulfonamide, by which it can be distinguished on polyacrylamide gels. This report describes both another isolation of a carbonic anhydrase from a source other than blood and the isolation of an inner-ear enzyme.
一种可溶性碳酸酐酶（碳酸水解酶，EC 4.2.1.1）已从豚鼠内耳的膜性外侧壁（血管纹、螺旋韧带、螺旋凸和外沟）中纯化至同质。膜性外侧壁中约1%的蛋白质是碳酸酐酶。该酶在外侧壁匀浆中的比活性是全血的1.6 - 1.8倍；对于血管纹和含螺旋韧带部分的匀浆，其比活性分别是全血比活性的0.9倍和2.0倍。所检测的其他耳蜗部分均不含可观的碳酸酐酶。纯化后的酶分子量约为30,000，比活性为血液中碳酸酐酶C的60 - 80%，电泳迁移率与血液中的酶相似。耳蜗碳酸酐酶在4×10⁻⁹M乙酰唑胺作用下活性被抑制一半，在乙酰唑胺浓度高于10⁻⁵M时被完全抑制，并且能与5 - 二甲基氨基萘 - 1 - 磺酰胺形成荧光复合物，借此可在聚丙烯酰胺凝胶上进行区分。本报告描述了从血液以外的来源分离碳酸酐酶以及分离内耳酶的另一种方法。
