芜菁（甘蓝型油菜紫顶白球变种）根中一种中性过氧化物酶同工酶的纯化及性质

Purification and properties of a neutral peroxidase isozyme from turnip (Brassica napus L. Var. Purple Top White Globe) roots.

作者信息

Duarte-Vázquez M A, García-Almendárez B E, Regalado C, Whitaker J R

机构信息

Departamento de Investigación y Posgrado en Alimentos, PROPAC, Facultad de Química, Universidad Autónoma de Querétaro, C. U. Cerro de Las Campanas, Querétaro, Qro. 76010, Mexico.

出版信息

J Agric Food Chem. 2001 Sep;49(9):4450-6. doi: 10.1021/jf010043e.

DOI:10.1021/jf010043e

PMID:11559153

Abstract

A neutral peroxidase isozyme (pI 7.2) from turnip roots (TNP) was purified to homogeneity and partially characterized. TNP is a monomeric glycoprotein with 9.1% carbohydrate content and a molecular weight of 36 kDa. Optimum pH values for activity using 2,2'-azinobis(3-ethylbenzthiazoline-6-sulfonic acid (ABTS) and guaiacol as H donors were 4.5 and 5.5, whereas the K(m) values were 0.7 and 3.7 mM, respectively. The ABTS K(m) was approximately 7 times higher than that reported for basic commercial horseradish peroxidase (HRP-C). TNP retained approximately 70% activity after 11 min of heating at 65 degrees C, whereas the activation energy for inactivation (132 kJ/mol) was higher than or comparable to that of other peroxidases. The low ABTS K(m) and high specific activity (1930 units/mg) gave a high catalytic efficiency (500 M(-1) s(-1)). These properties make TNP an enzyme with a high potential as an alternative to HRP in various applications.

摘要

从芜菁根中纯化出一种中性过氧化物酶同工酶（pI 7.2）（TNP）并对其进行了部分特性鉴定。TNP是一种单体糖蛋白，碳水化合物含量为9.1%，分子量为36 kDa。以2,2'-联氮双（3-乙基苯并噻唑啉-6-磺酸）（ABTS）和愈创木酚作为氢供体时，其活性的最适pH值分别为4.5和5.5，而米氏常数（K(m)）分别为0.7和3.7 mM。ABTS的K(m)约比碱性商业辣根过氧化物酶（HRP-C）报道的值高7倍。TNP在65℃加热11分钟后保留了约70%的活性，而其失活的活化能（132 kJ/mol）高于或与其他过氧化物酶相当。低ABTS K(m)和高比活性（1930单位/毫克）赋予了TNP高催化效率（500 M(-1) s(-1)）。这些特性使TNP在各种应用中成为一种极具潜力的替代HRP的酶。