Keywords: proteases, Solanum granuloso leprosum, cysteine peptidase, fruit protease, enzyme purification, characterisation, biotechnology, industrial waste, environmental contamination
Characterisation, stabilisation and possible biotechnological applications of new proteolytic enzymes from Solanum granuloso-leprosum
An extract possessing proteolytic activity was obtained by grinding the ripe fruit Solanum granuloso-leprosum, a tree of the family Solnaceae. The crude extract had maximum activity at pH between 5.2 and 7.6, and temperatures between 50°C and 55°C. It was stable at pH 7.6 and freezing temperature. The proteolytic activity of this plant product was activated and stabilised by reducing agents. Purification was carried out using simple and economical procedures, including ethanolic precipitation and gel-filtration chromatography. The main proteolytically active fraction obtained was inhibited by iodoacetamide and E-64, indicating its cysteinic nature. This fraction had a pI range of 7.5–8.3. The enzyme preparation was unstable at temperature above 4°C, but was stabilised by adsorption onto alumina. Its hydrolytic action was studied on casein whey and haemoglobin substrates, which represent ecologically contaminating fractions of industrial waste.