The effects of norepinephrine on lactoperoxidase enzyme (LPO)
The effects of norepinephrine on lactoperoxidase enzyme (LPO)
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发表时间：
2010-06
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通讯作者：
M. Şişecioğlu;I. Gülçin;M. Cankaya;A. Atasever;H. Özdemir
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作者：
M. Şişecioğlu;I. Gülçin;M. Cankaya;A. Atasever;H. Özdemir
去甲肾上腺素是一种激素和神经递质，被称为儿茶酚胺。在本研究中，我们检查了去甲肾上腺素对从牛奶中纯化的乳过氧化物酶的抑制作用。乳过氧化物酶（LPO；E.C.1.11.1.7）通过三个纯化步骤从牛奶中纯化：分别为 Amberlite CG-50 树脂、CM-Sephadex C-50 离子交换色谱和 Sephadex G-100 凝胶过滤色谱。 LPO纯化得率为31.5%，比活为30.33 EU/mg蛋白，纯化倍数为20.77。为了确定酶纯度，进行 SDS-PAGE 并观察单条带。 LPO 的 Rz (A412/A280) 值为 0.9。使用 ABTS 作为显色底物测定去甲肾上腺素对乳过氧化物酶的影响。发现去甲肾上腺素的半数最大抑制浓度 (IC50) 值为 67.2 µM。此外，去甲肾上腺素的抑制常数 (Ki) 为 62.0 µM。去甲肾上腺素被发现是非竞争性抑制剂。关键词：去甲肾上腺素，去甲肾上腺素，乳过氧化物酶，LPO，酶纯化，抑制。
Norepinephrine, a hormone and a neurotransmitter, was known as catecholamine. In the present study, we examined the inhibitory effect of norepinephrine on lactoperoxidase enzyme purified from bovine milk. Lactoperoxidase (LPO; E.C.1.11.1.7) was purified from bovine milk with three purification steps: Amberlite CG-50 resin, CM-Sephadex C-50 ion-exchange chromatography and Sephadex G-100 gel filtration chromatography, respectively. LPO was purified with a yield of 31.5%, a specific activity of 30.33 EU/mg proteins and 20.77 purification fold. To determine enzyme purity, SDS-PAGE was performed and single band was observed. The Rz (A412/A280) value for LPO was 0.9. The effect of norepinephrine on lactoperoxidase was determined using ABTS as a chromogenic substrate. The half maximal inhibitory concentration (IC50) value norepinephrine was found to be 67.2 µM. Also, inhibition constant (Ki) for norepinephrine was found to be 62.0 µM. Norepinephrine was found as non-competitive inhibitor. Key words: Noradrenaline, norepinephrine, lactoperoxidase, LPO, enzyme purification, inhibition.