荞麦种子中过氧化物酶的特性分析

Characterization of peroxidase in buckwheat seed.

作者信息

Suzuki Tatsuro, Honda Yutaka, Mukasa Yuji, Kim Sun-Ju

机构信息

National Agriculture Research Center for Hokkaido Region, Shinsei, Memuro, Kasai, Hokkaido 082-0071, Japan.

出版信息

Phytochemistry. 2006 Feb;67(3):219-24. doi: 10.1016/j.phytochem.2005.11.014. Epub 2006 Jan 3.

DOI:10.1016/j.phytochem.2005.11.014

PMID:16403545

Abstract

A peroxidase (POX)-containing fraction was purified from buckwheat seed. The POX consisted of two isozymes, POX I and POX II, that were purified 6.6- and 67.4-fold, respectively. Their molecular weights were estimated to be 46.1 kDa (POX I) and 58.1 kDa (POX II) by gel filtration. While POX I and II each oxidized quercetin, o-dianisidine, ascorbic acid and guaiacol, only POX II oxidized ABTS. Kinetic studies revealed that POX I and II had lower K(m) values for quercetin (0.071 and 0.028 mM), ABTS (0.016 mM for POX II) and ascorbic acid (0.043 and 0.029 mM) than for o-dianisidine (0.229 and 0.137 mM) and guaiacol (0.288 and 0 ). The optimum pHs of POX I and II for various substrates were almost the same, except for quercetin; pH 8.0 for POX I and pH 4.5 for II. Their optimal temperatures were 30 degrees C (POX I) and 10 degrees C (POX II), and POX I was more stable than POX II above 30 degrees C.

摘要

从荞麦种子中纯化出一个含过氧化物酶（POX）的组分。该POX由两种同工酶组成，即POX I和POX II，其纯化倍数分别为6.6倍和67.4倍。通过凝胶过滤法估计它们的分子量分别为46.1 kDa（POX I）和58.1 kDa（POX II）。虽然POX I和II都能氧化槲皮素、邻联茴香胺、抗坏血酸和愈创木酚，但只有POX II能氧化ABTS。动力学研究表明，POX I和II对槲皮素（0.071和0.028 mM）、ABTS（POX II为0.016 mM）和抗坏血酸（0.043和0.029 mM）的K(m)值低于对邻联茴香胺（0.229和0.137 mM）和愈创木酚（0.288和0）的K(m)值。除槲皮素外，POX I和II对各种底物的最适pH值几乎相同；POX I为pH 8.0，POX II为pH 4.5。它们的最适温度分别为30℃（POX I）和10℃（POX II），在30℃以上POX I比POX II更稳定。