Pectic enzymes associated with phosphate-stimulated infection of French bean leaves by Botrytis cinerea

1985 ◽  
Vol 91 (6) ◽  
pp. 253-264 ◽  
Author(s):  
J. Heuvel ◽  
L. P. Waterreus
Keyword(s):  
Botrytis Cinerea ◽  
French Bean ◽  
Pectic Enzymes ◽  
Bean Leaves

Purification and characterization of a constitutive polygalacturonase associated with the infection process of French bean leaves by Botrytis cinerea

1990 ◽  
Vol 68 (9) ◽  
pp. 1921-1930 ◽  
Author(s):  
G. Leone ◽  
E. A. M. Schoffelmeer ◽  
J. Van den Heuvel
Keyword(s):  
Botrytis Cinerea ◽  
Reaction Rate ◽  
French Bean ◽  
Infection Process ◽  
Purification Procedure ◽  
Purification And Characterization ◽  
Titration Curves ◽  
Optimal Ph ◽  
Bean Leaves

The constitutively produced polygalacturonase isoenzyme PG2 was isolated from culture filtrates of Botrytis cinerea, purified to homogeneity, and characterized. The shape of titration curves of PG2 and two other polygalacturonase isoenzymes explained the difficulties found in separating superimposed pectic enzyme activities during the purification procedure. PG2 hydrolyzed sodium polygalacturonate more quickly than pectin. The optimal pH for PG2 activity with polygalacturonate was 4.5 and with pectin, 4.0. PG2 activity was also influenced by the presence of NaCl or CaCl2 in the reaction mixture. Analysis of the breakdown products by paper chromatography and a comparison of the reaction rate by viscosimetry and reducing group assay revealed that PG2 has an endocatalytic mode of action on polygalacturonate. The isoelectric point and the molecular mass of PG2 were estimated to be 9.1 and 23.0 kDa, respectively. Key words: Botrytis cinerea, chromatofocusing, endopolygalacturonase, purification, substrate specificity, titration curve.

Regulation by carbohydrates of the sequential in vitro production of pectic enzymes by Botrytis cinerea

1987 ◽  
Vol 65 (10) ◽  
pp. 2133-2141 ◽  
Author(s):  
G. Leone ◽  
J. Van den Heuvel
Keyword(s):  
Botrytis Cinerea ◽  
Fungal Growth ◽  
French Bean ◽  
In Vitro Production ◽  
Pectic Polysaccharides ◽  
Pectic Enzymes ◽  
Conidial Concentration ◽  
Vitro Production ◽  
Polygalacturonase Activity

Cultures of Botrytis cinerea in a basal salt medium supplemented with different pectin-related polysaccharides (French bean cell walls; citrus pectin; sodium polygalacturonate) as the only carbon source were examined daily for polygalacturonase activity, type of pectic enzymes present, and mycelial growth. Total polygalacturonase activity and number of enzymes detectable were influenced by type and concentration of the substrate and by the conidial concentration at which the cultures were started. A consistent sequence in the production of pectic enzymes was found. The polygalacturonase PG2 was always the first enzyme present in the culture filtrates and was followed by a number of polygalacturonase and pectinesterase isoenzymes. PG2 was also found in ungerminated conidia. Its production is the expression of a constitutive gene as it was independent of the presence of the substrate and strictly correlated with fungal growth. D-Galacturonic acid at 2 mM induced the production of some of the pectic enzymes. At 10 mM and above, however, it repressed PG2 and the subsequent production of the whole pectic isoenzyme complex, indicating a feedback repression. The results suggest that the pectic isoenzymes produced by B. cinerea constitute a coordinated catabolic pathway for the complete degradation of pectic polysaccharides.

scholarly journals Radiochemical determination of a unique sequence around the reactive serine residue of a di-isopropyl phosphorofluoridate-sensitive plant carboxypeptidase and a yeast peptidase

1972 ◽  
Vol 128 (2) ◽  
pp. 229-235 ◽  
Author(s):  
D. C. Shaw ◽  
J. R. E. Wells
Keyword(s):  
Amino Acids ◽  
French Bean ◽  
Unique Sequence ◽  
Baker’S Yeast ◽  
Baker's Yeast ◽  
Serine Carboxypeptidase ◽  
Serine Residue ◽  
Radiochemical Determination ◽  
Bean Leaves

Phaseolain, a carboxypeptidase from French-bean leaves, and a partially purified peptidase from baker's yeast are inhibited by reaction with di-isopropyl phosphorofluoridate. Radioactive di-isopropyl [32P]phosphorofluoridate was used to show that the site of reaction is a unique serine residue and that the sequence of amino acids adjacent to the reactive serine is Glu-Ser-Tyr. This sequence is different from those of other ‘serine’ enzymes previously reported and, for phaseolain, represents an unequivocal example of a ‘serine’ carboxypeptidase.

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