School of Biotechnology, Maulana Abul Kalam Institute of Technology, BF142, Salt lake, Kolkata 700064, India.
School of Biotechnology, Maulana Abul Kalam Institute of Technology, BF142, Salt lake, Kolkata 700064, India.
Int J Biol Macromol. 2017 Nov;104(Pt A):929-935. doi: 10.1016/j.ijbiomac.2017.06.100. Epub 2017 Jun 27.
Flavonoids are dietary polyphenols that present abundantly in fruits and vegetables. Flavonoids have inhibitory effects on enzymes and catalase is one among them. Catalase is a common enzyme ubiquitously found in all living organisms exposed to oxygen. It catalyzes the decomposition of hydrogen peroxide to water and oxygen (2HO→2HO+O) Inhibition of pure and cellular catalase from K562 cells by flavonoids was similar and exhibited the following efficacy; Myrecetin>Quercetin>Kaempferol and Quercetin>Luteolin>Apigenin demonstrating structure activity relationship. Circular Dichroism (CD) spectra have shown distinct loss in α-helical structure of the catalase on interaction with the flavonoids. All flavonoids inhibited the catalase activity by uncompetitive mechanism. The K and V values of pure catalase were observed to be 294mM and 0.222mMs respectively and on inhibition with myrecetin the values decreased to a minimum of 23mM and 0.014mMs respectively. Inhibition of catalase will directly results in increased production of Reactive Oxygen Species (ROS) and pro-oxidant property of flavonoids. This inhibition was reversed in presence of Cu ions because of the chelating affect of flavonoids.
类黄酮是存在于水果和蔬菜中的饮食多酚。类黄酮对酶有抑制作用，其中包括过氧化氢酶。过氧化氢酶是一种普遍存在于所有暴露于氧气的生物中的常见酶。它催化过氧化氢分解为水和氧气（2HO→2HO+O）。类黄酮对纯过氧化氢酶和 K562 细胞过氧化氢酶的抑制作用相似，并表现出以下功效：杨梅素>槲皮素>山奈酚和槲皮素>木樨草素>芹菜素，表明结构活性关系。圆二色性（CD）光谱显示，过氧化氢酶的α-螺旋结构在与类黄酮相互作用时明显丧失。所有类黄酮均通过非竞争性机制抑制过氧化氢酶活性。纯过氧化氢酶的 K 和 V 值分别为 294mM 和 0.222mMs，而在用杨梅素抑制时，值降低至最小 23mM 和 0.014mMs。过氧化氢酶的抑制作用将直接导致活性氧（ROS）的产生增加和类黄酮的促氧化剂特性。由于类黄酮的螯合作用，Cu 离子的存在会逆转这种抑制作用。
