某些维生素对乳过氧化物酶活性的影响。

Effects of some vitamins on lactoperoxidase enzyme activity.

机构信息

Ataturk University, Science Faculty, Department of Chemistry, Erzurum, Turkey.

出版信息

Int J Vitam Nutr Res. 2009 May;79(3):188-94. doi: 10.1024/0300-9831.79.3.188.

DOI:10.1024/0300-9831.79.3.188

PMID:20209470

Abstract

OBJECTIVE

The present paper investigates the in vitro effect of L-ascorbic acid (vitamin C), menadione sodium bisulfate (vitamin K3), and folic acid on purified lactoperoxidase (LPO).

METHODS

This enzyme was purified from bovine milk by Amberlite CG 50 resin, CM Sephadex C-50 ion-exchange chromatography, and Sephadex G-100 gel filtration chromatography.

RESULTS

Rz (A412/A280) value for the purified LPO was found to be 0.8. Lactoperoxidase was purified 20.45-fold with a yield of 28.8 %. Purity of enzyme was checked by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) method and a single band was observed. All tested vitamins caused inhibition of the enzyme activity and displayed a competitive type of inhibition mechanism. IC(50) values of these three vitamins were 2.03 microM, 0.025 mM, and 0.0925 mM, and the K(i) constants were 0.508+/-0.257 microM, 0.0107+/-0.0044 mM, and 0.0218+/-0.0019 mM respectively.

CONCLUSION

The vitamins discussed here displayed inhibition-type competition with LPO enzyme at varying concentrations. Our study showed that L-ascorbic acid exhibited a much higher inhibitory effect at lower concentrations, so it was evidently a more potent inhibitor than other vitamins tested.

摘要

目的

本研究旨在探讨抗坏血酸（维生素 C）、甲萘醌亚硫酸氢钠（维生素 K3）和叶酸对纯化乳过氧化物酶（LPO）的体外影响。

方法

本实验通过 Amberlite CG 50 树脂、CM Sephadex C-50 离子交换层析和 Sephadex G-100 凝胶过滤层析从牛初乳中纯化 LPO。

结果

发现纯化 LPO 的 Rz（A412/A280）值为 0.8。乳过氧化物酶经 Amberlite CG 50 树脂、CM Sephadex C-50 离子交换层析和 Sephadex G-100 凝胶过滤层析纯化 20.45 倍，收率为 28.8%。酶的纯度通过十二烷基硫酸钠-聚丙烯酰胺凝胶电泳（SDS-PAGE）方法进行检查，观察到单一带。所有测试的维生素均抑制了酶的活性，并表现出竞争性抑制机制。这三种维生素的 IC50 值分别为 2.03 μM、0.025 mM 和 0.0925 mM，K i 常数分别为 0.508±0.257 μM、0.0107±0.0044 mM 和 0.0218±0.0019 mM。