A novel peroxidase purified from Marsdenia megalantha latex inhibits phytopathogenic fungi mediated by cell membrane permeabilization

作者：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

来源：International Journal of Biological Macromolecules, 2017, 96: 743-753.

DOI：10.1016/j.ijbiomac.2016.12.083

• Marsdenia megalantha
• Latex
• Peroxidase
• Antifungal protein
• Fusarium
• Protein defense

An antifungal class III peroxidase was purified from Marsdenia megalantha latex (named Mo-PDX) using DEAE-cellulose and gel filtration chromatography on a Superose 12 HR 10/30 column. Mm-PDX has an apparent molecular mass of 67.0 kDa 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-PDX were 5.0-7.0 and 60 degrees C, respectively. The catalytic activity of Mm-PDX 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-PDX 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-PDX also induced oxidative stress in F. solani. Mm-PDX 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.

• 出版日期2017-3