Biochemical pulping. Part XX Pectin lyase originating from Erwinia chrysanthemi with a low maceration potential.

Abstract

A mechanistic investigation of the maceration of mitsumata (Edgeworthia papyrifera Sieb. et Zucc) bast by pectinolytic enzymes from Erwinia chrysanthemi GIR 2002 was performed. Of the two maceration factors, endo-pectate lyase and endo-pectin lyase (endo-PNTE), endo-PNTE showed only a slight maceration potential in spite of possessing high enzyme activity. The isoelectric point and affinity toward partially esterified pectins of this enzyme were considerably lower than those of endo-PNTE from E. carotovora FERM P-7576. In the presence of Ca2 +, an ion which is supposed to screen the negative charges on pectic substances, PNTE of strain GIR 2002 improved as to this affinity and the maceration potential, the same levels as those in the case of the enzyme from FERM P-7576 almost being attained. It was strongly suggested that the low maceration activity of the enzymes from GIR 2002 was due to the malfunctioning of endo-PNTE due to ionic repulsion between the negative charges on the enzyme molecule and those o...