Isolation, purification and characterization of a protease from the seeds of Artocarpus heterophyllus

Proteases are being widely used in various industries like detergent, leather, food and pharmaceuticals.Protease was purified to homogeneity from the seeds of Artocarpus heterophyllus. The enzyme was found to be a tetramer having molecular mass of 74 kDa. Gelatin zymography showed a clear band of proteolysis. The enzyme isolated and purified was a serine protease, as indicated by its inhibition with PMSF. The enzyme was stable at broad pH and temperature ranges with pH and temperature optima at 8.5 and 50°C, respectively. The presence of some divalent ions enhanced the activity. With the addition of calcium, change in absorption and emission spectra was observed in spectrofluorometric analysis. The Km and Vmax for the enzyme was found to be 0.229 µM and 0.014 µM min-1, respectively, using BAPNA as a substrate. The enzyme consisted 4.44% alpha helix and 44.17% beta sheets when measured by CD spectra. Dynamic light scattering of the protease for particle size distribution revealed the mono-dispersity of the sample. Easy purification and paramount stability of protease makes it a good candidate for industrial and pharmaceutical applications.