Taylor, R. J., and Secor, G. A. 1988. An improved diffusion assay for quantifying the polygalacturonase content of Erwinia culture filtrates. Phytopathology 78:1101-1103. The agar diffusion procedure for quantifying pectolytic enzyme activity punched in the agarose with a # 1 cork borer. After incubation at 37 C for 17 was modified to optimize assay sensitivity and simplify its implementation. ...

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...

During the ripening of avocado (Persea americana) fruit, extensive cell wall degradation leads to a dramatic softening of the mesocarp tissue. Two enzymes have been suggested to play a critica1 role in this ripening-associated cell wall degradation in many fruits, including avocado, viz. cellulase (endo-~-1,4-glucanase) and endo-PG (Awad and Young, 1979; Fischer and Bennett, 1991). Although the...

The range of polysaccharide-degrading enzymes and glycosidases formed by the phytopathogenic fungus Sclerotinia sclerotiorum was monitored following growth on 16 carbohydrate substrates. Endo- and exoenzymes capable of degrading cellulosic, hemicellulosic, and pectinolytic polysaccharides were secreted. Pectinolytic activities were produced constitutively on all of the substrates tested. Cellul...