Purification of Solanum elaeagnifolium aspartic proteases (SEAPS) with antimicrobial activity

SILVA BELMARES, S.Y.; MUÑOZ, F.F.; GONZÁLEZ ZAVALA, M. A.; DE LA CRUZ GALICIA, M.G.; DALEO, G.R.; GUEVARA, G.R.

Mendoza

Congreso; XLVIII Reunión Anual SAIB; 2012

SAIB

Solanum elaeagnifolium (trompillo or silverleaf nightshade) is an endemic plant from the northeast of Mexico and southwest of United States. This plant in some places of Mexico has been used for decades in the manufacture of artisanal filatatype asadero cheese. The milk-clotting activity of S. elaeagnifolium has been attributed to aspartic proteases. The aim of this work was to purify aspartic proteases from leaves of S. elaeagnifolium. Purification was performed fromleaves of S. eleagnifolium by ammonium sulfate precipitation; ion exchange chromatography and Pepstatin A affinity chromatography. SDS-PAGE analysis of proteins eluted from the affinity column revealed three bands (SeAPs) with molecular weights of 86, 45 and 27 kDa approximately. In order to identify these proteins, bands were recovered, digested with trypsin and submitted to a MALDITOF spectrometric analysis. Proteins corresponding to the three bands isolated, matched with the sequences of plant aspartic proteases, specifically with potatoaspartic proteases (StAPs). Additionally, we determined that, like StAPs, SeAPs were able to interact and permeabilize microorganism plasma cell membranes, and exert cytotoxic activity in a dose- dependent manner. These results suggest the presence of saposin-like domain into the sequences of mature SeAPs and therefore, new biotechnological applications for SeAPs.