来自日本对虾（甲壳纲：十足目）肝胰腺的一种唾液酸酶：与酸性β-半乳糖苷酶的可逆结合。

A sialidase from the hepatopancreas of the shrimp Penaeus japonicus (Crustacea: Decapoda): reversible binding with the acidic beta-galactosidase.

Chuang N N, Yang B C

Division of Biochemistry and Molecular Science, Institute of Zoology, Academia Sinica, Nankang, Taipei, Taiwan, Republic of China.

Comp Biochem Physiol C Comp Pharmacol Toxicol. 1990;97(2):353-6. doi: 10.1016/0742-8413(90)90153-z.

Abstract

The sialidase purified from the hepatopancreas of Penaeus japonicus is able to bind the acidic beta-galactosidase in vitro. No protective protein, Mr 32,000, was detected in either purified enzyme preparation. 2. The specific activity of the isolated sialidase is 55.0 mU/mg of protein. After polyacrylamide gel electrophoresis under denaturing conditions, the purified shrimp enzyme was found to consist of monomers of Mr 32,000. 3. The sialidase from shrimp has an isoelectric point (pI) of 4.6 +/- 0.1. 4. The shrimp enzyme has the pH optimum at 5.0 and its Km was 5.5 microM with 2'-(4-methylumbelliferyl)-alpha-D-N-acetylneuraminic acid as substrate. The enzyme activity was inhibited by either Hg2+ or Cu2+ ions.

摘要

从日本对虾肝胰腺中纯化得到的唾液酸酶能够在体外与酸性β-半乳糖苷酶结合。在两种纯化酶制剂中均未检测到分子量为32,000的保护蛋白。2. 分离得到的唾液酸酶的比活性为55.0 mU/mg蛋白质。在变性条件下进行聚丙烯酰胺凝胶电泳后，发现纯化的虾酶由分子量为32,000的单体组成。3. 虾唾液酸酶的等电点（pI）为4.6±0.1。4. 虾酶的最适pH为5.0，以2'-（4-甲基伞形酮基）-α-D-N-乙酰神经氨酸为底物时其Km为5.5 microM。该酶活性受到Hg2+或Cu2+离子的抑制。