The intrinsic protein fluorescence of the polygalacturonase from Colletotrichium lindemuthianum was exploited in stopped-flow experiments aimed at elucidating the kinetic mechanism for this enzyme. Binding of the polymeric substrate polygalacturonic acid (PGA) essentially produced a triphasic fluorescence profile. There was an initial rapid quench in fluorescence, consistent with the rapid form...

Pectins from apple, citrus and sugar beet injected intravenously to ewes markedly stimulated blood prolactin, growth hormone (GH) and cortisol. Pectic acid and polygalacturonic acid exhibited the same property. A preparation of oligogalacturonic acid with a polymerisation degree of 12 to 13 was also active, whereas oligomers with a smaller degree of polymerisation ( ! 10) were devoid of activit...

Recently, it has been suggested that pectinases could be used to hydrolyze pectin in biorefineries based on pectin-rich agro-industrial wastes. However, for this to be viable, the cost of their production would need to be lowered significantly. In fact, over the last few decades, there have been many attempts to improve pectinase production by existing strains or to screen for new strains from ...

Yeast polygalacturonase (YPG) catalyzes the hydrolysis of pectic acid to a mixture of digalacturonic and galacturonic acids (1). The reaction course consists of (a) an initial rapid attack on the linear chain by a random mechanism until about 25 per cent hydrolysis has occurred, (b) a slower phase during which an additional 25 per cent of the available bonds are broken, and (c) an extremely slo...

A high-performance size-exclusion chromatography-evaporative light scattering detector method was used to separate, detect and quantify galacturonic acid (GA) oligomers. In 40 mM acetic acid GA monomer, dimer and trimer could be separated with baseline resolution but polygalacturonic acid (PGA) precipitated and could not be eluted from the column. An NH4OAc, pH 3.7, buffer was developed as the ...

We identified the d-galacturonic acid (GA)-responsive transcriptional activator GaaR of the saprotrophic fungus, Aspergillus niger, which was found to be essential for growth on GA and polygalacturonic acid (PGA). Growth of the ΔgaaR strain was reduced on complex pectins. Genome-wide expression analysis showed that GaaR is required for the expression of genes necessary to release GA from PGA an...