Evaluation of cytotoxic activity of mono-PEGylated AP3 ( aspartic protease 3) forms.

AP3 is a plant aspartic protease with cytotoxic activity toward a broad spectrum of pathogens, including potato and human pathogen microorganisms, and cancer cells, but not against human T cells, human red blood cells or plant cells. For this reason, AP3 could be a promising and potential drug candidate for future therapies. In this work, the improvement of the performance of AP3 was achieved by means of a modification with PEG. The separation of a mono-PEGylated AP3 fraction was easily performed by gel filtration chromatography. The mono-PEGylated AP3 fraction was studied in terms of antimicrobial activity, exhibiting higher antimicrobial activity against spores and , but slightly lower activity against than native protein. Such increase in antifungal activity has not been reported previously for a PEGylated plant protein. In addition, PEGylation did not affect the selective cytotoxicity of AP3, since no hemolytic activity was observed.