紫贻贝性腺β-N-乙酰氨基葡萄糖苷酶的纯化及性质（作者译）

[Purification and properties of beta-N-acetylglucosaminidase from Mytilus edulis L. gonads (author's transl)].

作者信息

Sánchez-Mozo P, Freire M, Vázquez-Pernas R, Ruiz-Amil M

出版信息

Rev Esp Fisiol. 1978 Jun;34(2):123-5.

Abstract

beta-N-Acetylglucosaminidase (beta-2-acetamido-2-deoxy-D-glucoside acetamidodeoxyglucohydrolase EC 3.2.1.30) from Mytilus edulis gonads and a homogenous protein was obtained from it by ion-exchange chromatography, gel filtration and disc electrophoresis. The apparent molecular weight, determined by gel filtration was 140,000 +/- 5,000. Two subunits were identified. The molecular weights of both subunits calculated by disc-electrophoresis were 70,000 and 75,000 + 2,000. Maximal activity for pH was 4.2. At 50 degrees C the enzyme was still active; at 60 degrees C inactive. The values of the apparent Km's proved to be 0.57 mM and 0.076 mM for p-nitrophenyl-beta-D-N-acetylglucosaminide and p-nitrophenyl-beta-D-N-acetylgalactosaminide as substrates. In the incubation of the enzyme with hyaluronic acid, chitin, deacetilated glycol-chitin and p-nitrophenyl-beta-D-glucuronide, N-acetyl-beta-D-glucosamine and glucuronic acid were not liberated. N-acetylgluconolactone and N-acetylgalactonolactone are competitive inhibitors for the enzyme.

摘要

从紫贻贝性腺中提取的β-N-乙酰氨基葡萄糖苷酶（β-2-乙酰氨基-2-脱氧-D-葡萄糖苷乙酰氨基脱氧葡萄糖水解酶，EC 3.2.1.30），通过离子交换色谱、凝胶过滤和圆盘电泳从中获得了一种均一蛋白质。通过凝胶过滤测定的表观分子量为140,000±5,000。鉴定出两个亚基。通过圆盘电泳计算的两个亚基的分子量分别为70,000和75,000 + 2,000。pH的最大活性为4.2。在50℃时酶仍有活性；在60℃时无活性。以对硝基苯基-β-D-N-乙酰氨基葡萄糖苷和对硝基苯基-β-D-N-乙酰半乳糖苷为底物时，表观Km值分别为0.57 mM和0.076 mM。在酶与透明质酸、几丁质、脱乙酰化的乙二醇几丁质和对硝基苯基-β-D-葡萄糖醛酸苷孵育时，未释放出N-乙酰-β-D-葡萄糖胺和葡萄糖醛酸。N-乙酰葡糖内酯和N-乙酰半乳糖内酯是该酶的竞争性抑制剂。