Oliveira Henrique P, Silva Rodolpho G G, Oliveira Jose T A, Sousa Daniele O B, Pereira Mirella L, Souza Pedro F N, Soares Arlete A, Gomes Valdirene M, Monteiro-Moreira Ana C O, Moreno Frederico B M B, Vasconcelos Ilka M
Department of Biochemistry and Molecular Biology, Federal University of Ceara, 60440-900 Fortaleza, CE, Brazil; University of International Integration of the Afro-Brazilian Lusophony, 62790-000 Redençao, CE, Brazil.
Department of Biochemistry and Molecular Biology, Federal University of Ceara, 60440-900 Fortaleza, CE, Brazil.
Int J Biol Macromol. 2017 Mar;96:743-753. doi: 10.1016/j.ijbiomac.2016.12.083. Epub 2017 Jan 3.
An antifungal class III peroxidase was purified from Marsdenia megalantha latex (named Mo-POX) using DEAE-cellulose and gel filtration chromatography on a Superose 12 HR 10/30 column. Mm-POX has an apparent molecular mass of 67.0kDa and a pI of 5.2, shares identity with other peroxidases, and follows Michaelis-Menten kinetics. It has a high affinity for guaiacol and hydrogen peroxide. The pH and temperature optima for Mm-POX were 5.0-7.0 and 60°C, respectively. The catalytic activity of Mm-POX was decreased in the presence of classic peroxidase inhibitors including azide, dithiothreitol, ethylenediamine tetraacetic acid, and sodium metabisulfite and high concentrations of Na, Mn, and salicylic acid. In contrast, Ca and Mg, even at low concentrations, enhanced the Mm-POX enzymatic activity. This protein inhibited the germination of the conidia of the phytopathogenic fungi Fusarium oxysporum and Fusarium solani by acting through a membrane permeabilization mechanism. Mm-POX also induced oxidative stress in F. solani. Mm-POX is the first enzyme to be isolated from the M. megalantha species and it has potential use in the control of plant disease caused by important phytopathogenic fungi. This adds biotechnological value to this enzyme.
采用DEAE - 纤维素和Superose 12 HR 10/30柱凝胶过滤色谱法，从牛奶菜（Marsdenia megalantha）乳胶中纯化出一种抗真菌III类过氧化物酶（命名为Mm - POX）。Mm - POX的表观分子量为67.0 kDa，pI为5.2，与其他过氧化物酶具有同源性，并遵循米氏动力学。它对愈创木酚和过氧化氢具有高亲和力。Mm - POX的最适pH和温度分别为5.0 - 7.0和60°C。在叠氮化物、二硫苏糖醇、乙二胺四乙酸和焦亚硫酸钠等经典过氧化物酶抑制剂以及高浓度的钠、锰和水杨酸存在时，Mm - POX的催化活性降低。相反，即使是低浓度的钙和镁也能增强Mm - POX的酶活性。该蛋白通过膜通透化机制抑制植物病原真菌尖孢镰刀菌（Fusarium oxysporum）和茄形镰刀菌（Fusarium solani）分生孢子的萌发。Mm - POX还能在茄形镰刀菌中诱导氧化应激。Mm - POX是从牛奶菜物种中分离出的首个酶，它在控制由重要植物病原真菌引起的植物病害方面具有潜在用途。这为该酶增添了生物技术价值。
