C1A cysteine peptidases are synthesized as inactive proenzymes. Activation takes place by proteol... more C1A cysteine peptidases are synthesized as inactive proenzymes. Activation takes place by proteolysis cleaving off the inhibitory propeptide. The inhibitory capacity of propeptides from barley cathepsin L and B-like peptidases towards commercial and barley cathepsins has been characterized. Differences in selectivity have been found for propeptides from L-cathepsins against their cognate and non cognate enzymes. Besides, the propeptide from barley cathepsin B was not able to inhibit bovine cathepsin B. Modelling of their three-dimensional structures suggests that most propeptide inhibitory properties can be explained from the interaction between the propeptide and the mature cathepsin structures. Their potential use as biotechnological tools is discussed.
Plant physiology and biochemistry : PPB / Société française de physiologie végétale, 2011
Protease inhibitors from plants have been involved in defence mechanisms against pests and pathog... more Protease inhibitors from plants have been involved in defence mechanisms against pests and pathogens. Phytocystatins and trypsin/α-amylase inhibitors are two of the best characterized protease inhibitor families in plants. In barley, thirteen cystatins (HvCPI-1 to 13) and the BTI-CMe trypsin inhibitor have been previously studied. Their capacity to inhibit pest digestive proteases, and the negative in vivo effect caused by plants expressing these inhibitors on pests support the defence function of these proteins. Barley cystatins are also able to inhibit in vitro fungal growth. However, the antifungal effect of these inhibitors in vivo had not been previously tested. Moreover, their in vitro and in vivo effect on plant pathogenous bacteria is still unknown. In order to obtain new insights on this feature, in vitro assays were made against different bacterial and fungal pathogens of plants using the trypsin inhibitor BTI-CMe and the thirteen barley cystatins. Most barley cystatins an...
Proteolysis is an essential process throughout the mobilization of storage proteins in barley gra... more Proteolysis is an essential process throughout the mobilization of storage proteins in barley grains during germination. It involves numerous types of enzymes, being the C1A cysteine proteases the most abundant key players. Manipulation of the proteolytic machinery is a potential way to enhance grain yield and quality and it could influence the mobilization of storage compounds along germination. Transgenic barley plants silencing or over-expressing the cathepsin F-like HvPap-1 cysteine protease show differential accumulation of storage molecules such as starch, proteins and free amino acids in the grain. It is particularly striking the HvPap-1 amiRNA lines phenotype which shows a drastic delay in the grain germination process. Alterations upon the proteolytic activities in the over-expressing and knock-down grains associated with changes in the level of expression of several C1A peptidases were also detected. Similarly, down-regulating cystatin HvIcy-2, one of the proteinaceous inhibitors of the cathepsin F-like protease, has also important effects on grain filling. However, the ultimate physiological influence of manipulating a peptidase or an inhibitor cannot be always predicted, since the plant tries to compensate the modified proteolytic effects by modulating the expression of some other peptidases or their inhibitors.
C1A cysteine peptidases are synthesized as inactive proenzymes. Activation takes place by proteol... more C1A cysteine peptidases are synthesized as inactive proenzymes. Activation takes place by proteolysis cleaving off the inhibitory propeptide. The inhibitory capacity of propeptides from barley cathepsin L and B-like peptidases towards commercial and barley cathepsins has been characterized. Differences in selectivity have been found for propeptides from L-cathepsins against their cognate and non cognate enzymes. Besides, the propeptide from barley cathepsin B was not able to inhibit bovine cathepsin B. Modelling of their three-dimensional structures suggests that most propeptide inhibitory properties can be explained from the interaction between the propeptide and the mature cathepsin structures. Their potential use as biotechnological tools is discussed.
Plant physiology and biochemistry : PPB / Société française de physiologie végétale, 2011
Protease inhibitors from plants have been involved in defence mechanisms against pests and pathog... more Protease inhibitors from plants have been involved in defence mechanisms against pests and pathogens. Phytocystatins and trypsin/α-amylase inhibitors are two of the best characterized protease inhibitor families in plants. In barley, thirteen cystatins (HvCPI-1 to 13) and the BTI-CMe trypsin inhibitor have been previously studied. Their capacity to inhibit pest digestive proteases, and the negative in vivo effect caused by plants expressing these inhibitors on pests support the defence function of these proteins. Barley cystatins are also able to inhibit in vitro fungal growth. However, the antifungal effect of these inhibitors in vivo had not been previously tested. Moreover, their in vitro and in vivo effect on plant pathogenous bacteria is still unknown. In order to obtain new insights on this feature, in vitro assays were made against different bacterial and fungal pathogens of plants using the trypsin inhibitor BTI-CMe and the thirteen barley cystatins. Most barley cystatins an...
Proteolysis is an essential process throughout the mobilization of storage proteins in barley gra... more Proteolysis is an essential process throughout the mobilization of storage proteins in barley grains during germination. It involves numerous types of enzymes, being the C1A cysteine proteases the most abundant key players. Manipulation of the proteolytic machinery is a potential way to enhance grain yield and quality and it could influence the mobilization of storage compounds along germination. Transgenic barley plants silencing or over-expressing the cathepsin F-like HvPap-1 cysteine protease show differential accumulation of storage molecules such as starch, proteins and free amino acids in the grain. It is particularly striking the HvPap-1 amiRNA lines phenotype which shows a drastic delay in the grain germination process. Alterations upon the proteolytic activities in the over-expressing and knock-down grains associated with changes in the level of expression of several C1A peptidases were also detected. Similarly, down-regulating cystatin HvIcy-2, one of the proteinaceous inhibitors of the cathepsin F-like protease, has also important effects on grain filling. However, the ultimate physiological influence of manipulating a peptidase or an inhibitor cannot be always predicted, since the plant tries to compensate the modified proteolytic effects by modulating the expression of some other peptidases or their inhibitors.
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