Inhibitory profile of latex-proteases in the genus Euphorbia

The latex of some plant families such as Apocynaceae, Asclepiadaceae, Asteraceae, Caricaceae, Convolvulaceae, Euphorbiaceae, and Moraceae are known to contain endopeptidases. 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. Nearly half of the commercially available enzymes are proteases, frequently used in food processing, tenderization of meat, brewing, cheese elaboration, bread manufacturing, leather and textile industries [1]. In the genus Euphorbia (Euphorbiaceae) 64 different species are mentioned to have proteolytic activity in their latices [2]. In this investigation the latex of 23 species of the genus Euphorbia, which are not characterised before, were collected in the Botanical Garden Berlin. To determine proteolytic activity we used the fluorogenic substrate BODIPY FL- casein (Moleculare Probes, Inc., USA) [3]. All tested samples show proteolytic activity. To investigate the type of endopeptidases, the latex samples were pre-incubated with specific inhibitors for serine (AEBSF (4-(2-Aminoethyl)-benzenesulfonyl fluoride hydrochloride)-, cysteine(E64 (4-(2-Aminoethyl)benzenesulfonylfluoride hydrochloride)) -, aspartatic (Pepstatin A)- and metalloprotease (EDTA) and the remaining activity was determined. 18 plants were strongly inhibited only by serine specific inhibitor, one plant was not influenced by any inhibitor and 4 plants were influenced by at least two inhibitors and had still a remaining proteolytic activity.

References: 1. Domsalla, A., Melzig, M.F. (2008) Planta Med 74:1–13.

2. Domsalla, A., Melzig, M.F. (2010) Pharmazie 65:227–230.

3. Menges, D.A. et al. (1997) Anal Biochem 251:144–147.