Biochemical and biophysical characterization of a peroxidase isolated from Euphorbia tirucalli with antifungal activity

by Shukla, A.; Gundampati, R. K.; Jagannadham, M. V.

A novel peroxidase from the latex of medicinal plant Euphorbia tirucalli (Pencil tree) belonging to the Euphorbiaceae family is purified to homogeneity using cation exchange chromatography. The enzyme, named Euphorbia tirucalli peroxidase (ETP) has a molecular mass of 38.8kDa. The isoelectric point of the enzyme is pH 7.5 with optimum pH and temperature of pH 6.0 and 50 degrees C respectively. The extinction coefficient ((1%)(280nm)) of the enzyme is 20.52 and the molecular structure consists of 13 tryptophan, nine tyrosine, and eight cysteine residues forming four disulfide bridges. Three peptide sequences, ALVHKECGPVVSCSDIVAIAARDSVVLTGGPKYDV, YYVDLMNRQGLFTSDQDLYT DKR, and MGQLEVVTGNQGEIR are obtained by MS/MS analysis which confirms the novelty of the enzyme. ETP belongs to / class of proteins with secondary structural features of approximately 10% -helix, 29% -sheet, and 61% random coil. ETP exhibits antifungal activity against Aspergillus niger and Candida albicans which shows its role in defense mechanism of plants. The enzyme is stable and retains its activity over a broad range of pH and temperature or prolonged storage at 4 degrees C. Simple purification, high yield, and stability enable exploration of the peroxidase for structure-function relationship studies as well as other biotechnological applications.

Journal
Biocatalysis and Biotransformation
Volume
34
Issue
5
Year
2016
Start Page
236-248
URL
https://dx.doi.org/10.1080/10242422.2016.1238463
ISBN/ISSN
1029-2446; 1024-2422
DOI
10.1080/10242422.2016.1238463