Purification and Properties of a Neutral Peroxidase Isozyme from Turnip (Brassica napus L. Var. Purple Top White Globe) Roots
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- 作者：Miguel A. Duarte-Vá ; zquez ; Blanca E. Garcí ; a-Almendá ; rez ; Carlos Regalado ; and John R. Whitaker
- 刊名：Journal of Agricultural and Food Chemistry
- 出版年：2001
- 出版时间：September 2001
- 年：2001
- 卷：49
- 期：9
- 页码：4450 - 4456
- 全文大小：114K
- 年卷期：v.49,no.9(September 2001)
- ISSN：1520-5118
文摘
A neutral peroxidase isozyme (pI 7.2) from turnip roots (TNP) was purified to homogeneity andpartially characterized. TNP is a monomeric glycoprotein with 9.1% carbohydrate content and amolecular 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 Km valueswere 0.7 and 3.7 mM, respectively. The ABTS Km was ~7 times higher than that reported for basiccommercial horseradish peroxidase (HRP-C). TNP retained ~70% activity after 11 min of heatingat 65 
C, whereas the activation energy for inactivation (132 kJ/mol) was higher than or comparableto that of other peroxidases. The low ABTS Km and high specific activity (1930 units/mg) gave ahigh catalytic efficiency (500 M-1 s-1). These properties make TNP an enzyme with a high potentialas an alternative to HRP in various applications.Keywords: Neutral peroxidase; turnip roots; protein purification
C, whereas the activation energy for inactivation (132 kJ/mol) was higher than or comparableto that of other peroxidases. The low ABTS Km and high specific activity (1930 units/mg) gave ahigh catalytic efficiency (500 M-1 s-1). These properties make TNP an enzyme with a high potentialas an alternative to HRP in various applications.Keywords: Neutral peroxidase; turnip roots; protein purification