Table I.

Classification of cysteine proteinases of the papain super family

Type and Characteristic Features	Predicted Roles	Examples	Reference
From leguminous plants
A Nodule specific with an LQDA motif	Protein turnover, remodeling of tissues, cell cycle component, defence response to microbial invasion	AsNODf32 (Chinese milk vetch)AgNOD-CP1 (A. glutinosa)	Goetting-Minesky and Mullin (1994)
B Nodule specific without an LQDA motif	Degradation of senescent nodule cells and bacteroids	PsCyp1 (pea)	Kardailsy and Brewin (1996)
C Expressed in oil bodies localized in vacuoles	Storage protein degradation for recycling, binds to sylingilide elicitor	P34 (soybean)	Kalinski et al. (1990)
D Expressed in cotyledons with a KDEL motif	Degradation of storage protein in seeds	pSK19 (vetch)SH-EP (V. mungo)	Becker et al. (1997),Akasofu et al. (1989)
E Expressed in cotyledons without a KDEL motif	Degradation of storage protein in seeds	PvCEP-1 (P. vulgaris)	Sohlberg and Sussex (1997)
F Expressed in all tissues	Unknown	PsCyp15a (pea)	Kardailsky and Brewin (1996)
From non-leguminous plants
G With a signal peptide for transportation to vacuole	Degradation of a specific protein responding to fungal infection, tolerance mechanism to suboptimal conditions, involved in leaf senescence, peptide degradation in ripe fruits, and degradation of storage proteins during germination	LCYP-2 (tomato)ZMSsel (maize)P21 (petunia)pARP152 (Prunus armeniaca)PM33cysP (P. menziesii)	Linthorst et al. (1993),Griffiths et al. (1997),Tournaire et al. (1996),Mbeguie-A-Mbeguie et al. (1997),Tranbarger and Misra (1996)
H With a signal peptide for transportation to ER	Programmed cell death in flower senescence and expressed in ovules during seed formation	SEN11 (Hemerocallis sp.)O141 (Phalaenopsis sp.)	Guerrero et al. (1998),Nadeau et al. (1996)