%0 Journal Article
%A Martinez, Manuel 
%A Díaz Mendoza, María Mercedes
%A Carrillo, Laura 
%A Diaz, Isabel 
%T Carboxy terminal extended phytocystatins are bifunctional inhibitors of papain and legumain cysteine proteinases
%D 2007
%@ 0014-5793
%U https://hdl.handle.net/20.500.14352/94326
%X Plant legumains are cysteine proteinases putatively involved in processing endogenous proteins. Phytocystatins (PhyCys) have been described as plant inhibitors of papain-like cysteine proteinases. Some PhyCys contain a carboxy terminal extension with an amino acid motif (SNSL) similar to that involved in the inhibition of legumain-like proteins by human cystatins. The role of these carboxy terminal extended PhyCys as inhibitors of legumain-like cysteine proteinases is here shown by in vitro inhibition of human legumain and legumain-like activities from barley extracts. Moreover, site-directed mutagenesis has demonstrated that the asparagine of the SNSL motif is essential in this inhibition. We prove for first time the existence of legumain inhibitors in plants.
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