A comparative study of the role of the major proteinases of germinated common bean (Phaseolus vulgaris L.) and soybean (Glycine max (L.) Merrill) seeds in the degradation of their storage proteins

Abstract

Two types of cysteine proteases, low-specificity enzymes from the papain family and Asn-specific from the legumain family are generally considered to be the major endopeptidases responsible for the degradation of seed storage proteins during early seedling growth. The action of the corresponding enzymes (CPPh1 and LLP, respectively) from common bean (Phaseolus vulgaris L.) on phaseolin (the common bean storage protein), and on the homologous soybean (Glycine max (L.) Merrill) storage protein, beta-conglycinin, was studied. Under the action of LLP, proteolysis of phaseolin was limited to cleavage of its interdomain linker. No cleavage of the interdomain linker occurred in beta-conglycinin with LLP. LLP action was restricted to splitting off the disordered N-terminal extensions of alpha and alpha' subunits. No extensive hydrolysis (degradation to short TCA-soluble peptides) of either protein occurred under the action of LLP. CPPh1 cleaved the phaseolin subunits into roughly half-sized fragments at the onset of proteolysis. The cleavage was accompanied by a small (8-10%) decrease of protein. No decrease of protein occurred with further incubation. Thus the two most active proteinases detected in common bean seedlings individually were incapable of the extensive degradation of phaseolin. Extensive hydrolysis of phaseolin was only achieved by the consecutive action of LLP and CPPh1. Similar cleavages occurred during the action of CPPh1 on beta-conglycinin. However, by contrast with phaseolin, CPPh1 by itself accomplished the extensive hydrolysis of beta-conglycinin. The differences in the course of proteolysis of the proteins studied were determined by their structural peculiarities.

Germination of Phaseolus vulgaris and alcalase hydrolysis of its proteins produced bioactive peptides capable of improving markers related to type-2 diabetes in vitro

“…During germination, the proteins started to be degraded by endopeptidases, located in the cotyledons, forming oligopeptides. The oligopeptides are then hydrolyzed by exopeptidases in order to form free amino acids, which will be used to synthesize new proteins and tissues (Sangronis et al, 2006;Zakharov et al, 2004).…”

“…During germination, several biochemical mechanisms are activated such as the hydrolysis of starch and proteins, in order to meet the needs of the new plant (Klose & Arendt, 2012). Endopeptidases degrade storage proteins producing oligopeptides, which are further degraded by exopeptidases forming free amino acids (Sangronis, Rodríguez, Cava, & Torres, 2006;Zakharov, Carchilan, Stepurina, Rotari, Wilson, & Vaintraub, 2004).…”

Storage proteins and cell wall mobilisation in seeds of Sesbania virgata (Cav.) Pers. (Leguminosae)

“…4, 5), it can be suggested that there seems to exist synthesis de novo of some proteases during and after germination, which are necessary to the storage protein mobilisation. Proteases are involved in the storage proteins hydrolyses and many of these enzymes are synthesised de novo during and after germination (Cervantes et al 1994;Bewley 1997;Asano et al 1999;Buckeridge et al 2004b;Zakharov et al 2004). In seeds of tomato, it has been observed that the actinomycin-D inhibits the proteases activities during the post-germinative process (Mathan 1965).…”

Identification and Purification of Metalloprotease from Dry Grass Pea (Lathyrus sativus L.) Seeds

“…Proteolytic enzymes are intricately involved in many aspects of plant physiology and development [2,4]. Numerous reports including our previous data supported that the proteases are responsible for protein degradation [5][6][7][8][9][10]. With renewed interest, there has been proliferation of reports in the last decade concerning purification and characterization of these proteases from leguminous and nonleguminous seeds [2,[11][12][13][14][15][16].…”