Table 1.

Overview of toxic plant proteins.

Family	Source	Structural features	Biological activity	References
Lectin	Ubiquitous in plants	One or more CRDs	Carbohydrate-binding activity	Van Damme et al., 2008, Van Damme, 2014
Ribosome-inactivating proteins	Widely distributed	N-glycosidase domain	N-glycosidase activity	Peumans et al., 2001, Shang et al., 2014
Protease inhibitors/α-amylase inhibitors	Widely distributed, rich in storage tissues	N/A	Inhibition of protease/α-amylase	Leung et al., 2000, Murdock and Shade, 2002, Svensson et al., 2004
Urease and canatoxin-like proteins	Mainly in legumes	A 10 kDa region, with a β-hairpin motif	Ureolytic activity Pore-forming activity	Follmer et al., 2001, Barros et al., 2009
Arcelins	Seeds of Phaseolus sp.	Legume lectin fold	N/A	Acosta-Gallegos et al., 1998, Zaugg et al., 2013
Thionins	A number of monocot and dicot plants	∼5 kDa cysteine containing proteins	Increase of cell membrane permeability	Stec (2006)
Cyclotides	Widely distributed	Cyclic cysteine knot	Pore-forming activity	Craik et al. (2012)
Pore-forming toxins	Some plants, e.g. Enterolobium contortisiliquum, wheat	Membrane-spanning region (ß-barrel/α-helical)	Pore-forming activity	Bittencourt et al., 2003, Puthoff et al., 2005