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The objective of this study was to purify, characterize, and phylogenetically and structurally analyze the dextranase produced by the fungus . Dextranase produced by the fungus was purified to homogeneity in two steps, with a yield of 152%, purification factor of 6.84 and specific activity of 358.63 U/mg. Its molecular weight was estimated by SDS-PAGE at 64 kDa. The enzyme presented higher activity at 50 °C and pH 5.0, using 100 mM citrate-phosphate buffer, was inhibited by Ag, Hg, Cu, Mg, and presented K of 23.60 µM. Mature dextranase is composed of 585 amino acids residues, with a predicted molecular weight of 64.38 kDa and pI 5.96. This dextranase showed a strong phylogenetic similarity when compared to dextranase. Its structure consists of two domains: the first composed by 15 β strands, and the second composed by a right-handed parallel β-helix.

Synadenium grantii is a Euphorbiaceae plant commonly found in Brazil, known as Janaúba or Leitosinha, whose latex is traditionally used for several purposes. However, it is not known whether the nematicidal action of this plant latex occurs due to the action of proteases. The present work aims to evaluate the nematicidal activity of proteases from Synadenium grantii latex on Meloidogyne incognita and Panagrellus redivivus. S. grantii latex used in the present study was collected from specimens found in Universidade Federal de Viçosa, Viçosa, Minas Gerais, Brazil. The drained latex was collected in Eppendorf microtubes and immediately stored on ice at 4 °C. After this extraction, the latex was frozen (-20 °C) during 2 hours, thawed at room temperature (25 °C) and centrifuged at 10,000 g at 4 °C for 30 minutes to remove larger particles and concentrate the proteases. After the centrifugation, assays of enzymatic activity were performed in order to know in which of the phases the enzymes were found. S. grantii latex presented protease, but no chitinase activity. The results show that there was a significant difference (p <0.01) between the treated and control groups, with 100% mortality of Meloidogyne incognita and 72% average mortality of Panagrellus redivivus. In addition, it was demonstrated that the nematicidal action occurred due to the action of the proteases, since the control was only differentiated from the treatment by the presence of the enzymes with biological activity.

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