Purification and characterization of a novel chitinase from Trichosanthes dioica seed with antifungal activity

• A novel chitinase (TDSC) was purified with the Mr. of 39 ± 1 kDa from Trichosanthes dioica seed.
• TDSC was glycoprotein in nature and the N-terminal sequence was EINGGGA.
• TDSC was rich in leucine and stable in a wide range of temperature and pH.
• Ca2+, EDTA and urea were slight inhibitors of the enzyme.
• TDSC showed antifungal activity against Aspergillus niger and Trichoderma sp.

Chitinases are a group of enzymes that show differences in their molecular structure, substrate specificity, and catalytic mechanism and widely found in organisms like bacteria, yeasts, fungi, arthropods actinomycetes, plants and humans. A novel chitinase enzyme (designated as TDSC) was purified from Trichosanthes dioica seed with a molecular mass of 39 ± 1 kDa in the presence and absence of β-mercaptoethanol. The enzyme was a glycoprotein in nature containing 8% neutral sugar. The N-terminal sequence was determined to be EINGGGA which did not match with other proteins. Amino acid analysis performed by LC-MS revealed that the protein was rich in leucine. The enzyme was stable at a wide range of pH (5.0–11.0) and temperature (30–90 °C). Chitinase activity was little bit inhibited in the presence of chelating agent EDTA (ethylenediaminetetraaceticacid), urea and Ca2+. A strong fluorescence quenching effect was found when dithiothreitol and sodium dodecyl sulfate were added to the enzyme. TDSC showed antifungal activity against Aspergillus niger and Trichoderma sp. as tested by MTT assay and disc diffusion method.