来自多花破布木种子的酸性α-半乳糖苷酶的特性及生物技术应用

Characterization and biotechnological application of an acid alpha-galactosidase from Tachigali multijuga Benth. seeds.

作者信息

Fialho Lílian da Silva, Guimarães Valéria Monteze, Callegari Carina Marin, Reis Angélica Pataro, Barbosa Daianny Silveira, Borges Eduardo Euclydes de Lima, Moreira Maurilio Alves, de Rezende Sebastião Tavares

机构信息

Departamento de Bioquímica e Biologia Molecular - BIOAGRO, Universidade Federal de Viçosa, Viçosa, MG 36570-000, Brazil.

出版信息

Phytochemistry. 2008 Oct;69(14):2579-85. doi: 10.1016/j.phytochem.2008.08.017. Epub 2008 Oct 2.

DOI:10.1016/j.phytochem.2008.08.017

PMID:18834998

Abstract

Tachigali multijuga Benth. seeds were found to contain protein (364 mg g(-1)dwt), lipids (24 mg g(-1)dwt), ash (35 mg g(-1)dwt), and carbohydrates (577 mg g(-1)dwt). Sucrose, raffinose, and stachyose concentrations were 8.3, 3.0, and 11.6 mg g(-1)dwt, respectively. alpha-Galactosidase activity increased during seed germination and reached a maximum level at 108 h after seed imbibition. The alpha-galactosidase purified from germinating seeds had an M(r) of 38,000 and maximal activity at pH 5.0-5.5 and 50 degrees C. The enzyme was stable at 35 degrees C and 40 degrees C, but lost 79% of its activity after 30 min at 50 degrees C. The activation energy (E(a)) values for p-nitrophenyl-alpha-d-galactopyranoside (pNPGal) and raffinose were 13.86 and 4.75 kcal mol(-1), respectively. The K(m) values for pNPGal, melibiose, raffinose, and stachyose were 0.45, 5.37, 39.62 and 48.80 mM, respectively. The enzyme was sensitive to inhibition by HgCl(2), SDS, AgNO(3), CuSO(4), and melibiose. d-Galactose was a competitive inhibitor (K(i)=2.74 mM). In addition to its ability to hydrolyze raffinose and stachyose, the enzyme also hydrolyzed galactomannan.

摘要

发现多对叶猴耳环种子含有蛋白质（364毫克/克干重）、脂质（24毫克/克干重）、灰分（35毫克/克干重）和碳水化合物（577毫克/克干重）。蔗糖、棉子糖和水苏糖的浓度分别为8.3、3.0和11.6毫克/克干重。α-半乳糖苷酶活性在种子萌发期间增加，并在种子吸胀后108小时达到最高水平。从萌发种子中纯化的α-半乳糖苷酶的相对分子质量为38000，在pH 5.0 - 5.5和50℃时具有最大活性。该酶在35℃和40℃稳定，但在50℃ 30分钟后失去79%的活性。对硝基苯基-α-D-吡喃半乳糖苷（pNPGal）和棉子糖的活化能（E(a)）值分别为13.86和4.75千卡/摩尔。pNPGal、蜜二糖、棉子糖和水苏糖的米氏常数（K(m)）值分别为0.45、5.37、39.62和48.80毫摩尔。该酶对HgCl₂、SDS、AgNO₃、CuSO₄和蜜二糖的抑制敏感。D-半乳糖是一种竞争性抑制剂（K(i)=2.74毫摩尔）。除了能够水解棉子糖和水苏糖外，该酶还能水解半乳甘露聚糖。