Proteolytic activity in the genus Euphorbia

Abstract

Over 110 latices of different plants are known to contain at least one proteolytic enzyme. Proteolytic enzymes from plant latex have received special attention in the pharmaceutical industry and biotechnology due to their property of being active over wide range of temperature and pH. In the latex of Euphorbiaceae only proteolytic endopeptidases of the subclass serine proteases (EC 3.4.21) are mentioned in the literature [1]. For detecting proteolytic activity in the genus Euphorbia we collected latex of 30 different plants which are located in the Botanical Garden Berlin. To determine proteolytic activity we used the fluorogenic substrate BODIPY FL- casein (Moleculare Probes, Inc., USA) [2]. The change in fluorescence was compared to that produced by trypsin as standard; with a volume of 100µl of each trypsin concentration. The plants were divided into two groups; group I has its activity in the range between 5µg/ml and 2.5mg/ml trypsin (27 plants) and group II has a very strong proteolytic activity higher than 2.5mg/ml trypsin (3 plants). Proteolytic activity of latices in the genus Euphorbia could be expect as a chemotaxonomic characteristic because every tested sample was able to make a significant change in fluorescence compared to the control. To investigate if serine proteases are the active endopeptidases, the latex samples were pre-incubated with serine protease specific inhibitors (AEBSF (4-(2-Aminoethyl)-benzenesulfonyl fluoride hydrochloride) and Aprotinin) and the remaining activity was determined. 9 plants are not influenced by the inhibitors, 19 plants were influenced but had still a remaining proteolytic activity, and by 2 plants the residual activity was negligible.